my parrot. Having recently lost a closely bonded bird, my primary concern was to do everything
practical to improve the chances of recovering Flutters if he became lost. I thought that if I could
equip him with something like a Social Security number, I would greatly improve my chances of
recovering him. I therefore began to research the available information about RFID microchip
implants in companion animals.
The first thing that I discovered was that confusion about various aspects of RFID microchipping
is almost as plentiful as the information.
The second thing that I learned was that much of this confusion is due to conflicts between
microchip standards governing the RFID chips used in the United States and internationally.
How RFID Microchips Work & What They Can - and Cannot Do
RFID microchipping has become increasing more popular with companion animal owners in the
Unites States and Europe over the past decade. Although the microchipping of birds still lags far
behind the microchipping of dogs and cats, some parrot breeders have already started to
routinely microchip the birds that they sell to the public. In fact, the web site of
www.daddieo.homestead.com, a bird breeder in California, states, “We no longer band our
babies unless you have a deposit on (the) baby before three weeks old. You must tell us you
want your baby banded. We have lost too many pets and breeds due to the bands. We will
Microchip your baby for $43. Two of our vets agree with us.” Other breeders are also starting to
offer microchipping as an option to banding, or are making it their standard policy.
So what is this little piece of silicone that is attracting so much attention and even causing some
An RFID microchip is an electronic chip known as a “transponder.” It is about the size of a large
grain of rice. Its sole purpose is to uniquely identify the host into which it was implanted. It is
encapsulated in surgical glass and injected into a companion animal's body using a syringe. The
host then forms a layer of connective tissue around the implant. Because RFID microchips do
not have a power source that can run down, they can last the lifetime of most companion animals.
Digital Angel 125 kHz, ISO FDX-A, RFID Transponder
Marketed in the USA under the HomeAgain Brand Name
Courtesy HomeAgain / Digital Angel
RFID microchips capture some radio wave energy from the electronic scanner that is
interrogating them and then reflect it back to the scanner. In some respects, this is similar to the
way in which a mirror works with light, except that a mirror reflects back the image of the person
who is standing in front of it. The RFID chip reflects a unique, preprogramed “Social Security like”
number back to the scanner. The distance at which these transponders operate depends on the
chip and the scanner, but usually it ranges from a few inches to a few feet. Satellites in orbit
around the earth cannot read RFID transponders, as some have claimed.
All types of RFID microchips work in basically the same manner. However, RFID microchips
alone cannot identify a host animal. Identification of lost animals requires the support of a widely
distributed network of compatible scanners that can read the unique numbers on the implanted
microchips. A nationwide database which veterinarians and animal shelter personnel can easily
contact when a lost animal has been found is also required. This database associates the
number that appears on the scanner with the contact information of the owner of the lost animal.
These are the three “legs” upon which any system for identifying and recovering lost companion
animals must stand. The failure of owners to understand this and to keep their contact
information current with the database has already cost some companion animals their lives.
RFID transponders and scanners most commonly used in the United States for companion
animals operate at a frequency of 125 KHz. The design of these chips conforms to the old
FECAVA (Federation of European Companion Animal Veterinary Association) open standard
provided that the chips are not encrypted. However, the 125 KHz chip designs used in the United
States predate the FECAVA open standard. In fact the FECAVA standard was developed based
on the Destron Fearing system design. Consequently the term “FECAVA” is common throughout
much of the world, but is rarely used in the United States. ( Destron Fearing’s name was
changed to Digital Angel in September of 2000 after a merger. )
Only two companies, AVID and Digital Angel, market 125 kHz RFID transponder chips in the
United States. Digital Angel sells a 125 KHz open standard chip marketed under the “Home
Again” brand name. AVID also sells an open standard transponder chip known as the “Euro
Chip.” Both the HomeAgain chip and the EuroChip are functionally equivalent. Both reflect
back unique ten digit numbers when they are interrogated by a scanner. Neither one is encrypted
and both are suitable for use in the United States and overseas. However the name “EuroChip
may have caused some people to believe that it is only suited for use outside the United States.
This is not the case. The HomeAgain chip and the EuroChip qualify as ISO-A transponders.
More about this later.
AVID also sells a 125 kHz chip that they have encrypted to improve the security of the electronic
tag number against duplication. This chip reflects back an encrypted 9 digit number to the
scanner. The possibility of tag duplication on a large scale is a weakness to which every open
standard chip design is vulnerable. The problem of tag duplication is real. Whether it remains
manageable or becomes unmanageable is a question for the future. AVID markets the encrypted
125 kHz transponder under the “FriendChip” brand name. Generally, encrypted chips should not
be used outside of the United States due a lack of scanners that can read these chips.
These two companies also distribute scanners that can read or detect the ID numbers of each
other's 125 kHz chips. They maintain databases on a 24/7/365 basis which associate the RFID
transponder numbers with the owner’s contact information. When an animal shelter or
veterinarian scans the implanted nine or ten digit chip number in a lost animal, they must check
the AVID Pettrac database, the HomeAgain data base, and any other public database until they
find the animal's owner. Therefore, it is important to register your pet with the largest and best-
known databases after implanting the RFID transponder.
Typical 125 KHz Universal Scanner capable of reading both encrypted and unencrypted
RFID Transponders that are used in the USA as well as other ISO-A transponders.
Courtesy HomeAgain / Digital Angel
A Spring, 2002 article appearing in parrotchronicles.com stated that approximately 600,000
companion birds were implanted with AVID microchips at that time.
According to Dr. Silverman, Staff Veterinarian of AVID, approximately two million companion
birds have had AVID microchips implanted as of September, 2006. Birds as small as 50 grams
have been microchipped, although most veterinarians prefer not to microchip birds weighing less
than 100 grams. AVID will also register birds in their database using the leg band number. This
could potentially be useful to owners of small, banded, birds that are difficult to microchip.
AVID receives approximately 800 world wide daily calls on its lost animal database.
The database for the HomeAgain RFID chip showed 1259 companion birds microchipped in
Spring, 2002. Schering-Plough, who manages the database and markets the Home Again chips
in the United States, advises that currently 429 birds are enrolled in the Home Again database.
More birds may be implanted with the Home Again chip since some owners do not register with a
database once the chip has been implanted in their pet. This renders the entire microchipping
process useless. The Home Again database will also accept registrations of birds by their leg
By any measure, the increase in companion birds implanted with RFID microchips over the past
five years has been dramatic. However, due to the wide variances in the estimates of the
national population of cage and aviary birds, it is difficult to say in percentage terms how many
birds have been microchipped. A 2001 study of the caged bird population by the American Pet
Product Manufacturers Association (APPMA) estimated the number to be about 17.2 million birds
in 6.7 million households. This figure is close to the low end of the scale for cage and aviary bird
population estimates. A 1998 article in the Journal of the American Veterinary Medical
Association estimated the U.S. pet bird population at between 35 and 40 million with an annual
growth rate of approximately 5%.
That was the simple part of the microchip story.
Now the more complicated part begins.
The Switzerland-based International Standards Organization (ISO), of which the United States is
a member, has developed a standard for RFID transponders that work at a different frequency
than the RFID chips used in the United States. These "ISO" chips are governed by ISO
standards 11784 and 11785. They operate at a frequency of 134.2 KHz, and reflect back 15 digit
numbers. Such transponders are generally known as ISO FDX-B transponders. Because of the
difference in operating frequencies, scanners that work only at 125 kHz cannot read the 134.2
kHz ISO chip, and vice versa. This is similar to having a radio receiver without a tuner, that can
only operate at one frequency. If you wanted to listen to another station, you would have to buy a
different radio receiver specifically tuned to that station. Alternatively, you could buy a radio
receiver with a built-in tuner that would receive both stations. More than 100,000 of these “125
KHz only” scanners are in use within the United States.
Fully ISO-compliant scanners exist, are marketed outside the USA, and can read unencrypted
chips operating at both the 125 KHz frequency and the 134.2 KHz frequency. This is because
FECAVA technology has been grandfathered within the ISO standards. FECAVA-compliant
transponders fully comply with ISO 11785, Annex A and are known as ISO FDX-A transponders.
In other words the ISO standards provide for compatibility with open standard 125 KHz
transponders! These transponders are readily available within the United States from the two
leading RFID microchip manufacturers.
In an ideal world, using only fully ISO compliant scanners could be the best solution to reading all
ISO-compliant transponders operating at any frequency. In the real world things are never that
simple. Some foreign scanner manufacturers sell so-called “ISO scanners” that are not fully ISO
compliant because they only work at the 134.2 kHz frequency! This simple fact could escape
many potential users of these scanners, resulting in severe consequences for lost pets in the
The 134.2 kHz ISO FDX-B transponders are being used for companion animals in Europe and
other countries, along with the implanted base of ISO-A transponders. ISO FDX-B chips are
starting to be used in Canada. ISO FDX-B chips are the standard that the US Department of
Agriculture is using for its National Animal Identification System (NAIS) for food animals. The
American Veterinary Medical Association AVMA has also endorsed ISO RFID standards in April
of 1997 and reaffirmed this in November of 2005.
However, HR2744, which was signed into law in November 2005, does not require the use of ISO
technology for companion animals. Instead this bill requires the Animal and Plant Health
Inspection Service (APHIS) - a branch of the U.S. Dept. of Agriculture (USDA) —"...to develop
the appropriate regulations that allow for universal reading ability and best serve the interests of
pet owners." The same bill also instructs APHIS "...to take into consideration the effect such
regulation may have on the current practice of microchipping pets in this country"
APHIS appears to have forgotten about the scanners with universal reading ability that were the
focus of their charge by Congress. As part of the rule making process they have held public
hearings focused around the following question published in Volume 71 of the Federal Register
on March 10, 2006: “In this document we are seeking input from the public and stakeholders
regarding the use of microchips for identifying dogs and cats covered under the AWA and any
impacts there may be if we were to require ISO 11784 and 11785 compliant microchips when
microchipping dogs and cats for identification under AWA.”
APHIS also clarifies their position concerning US national microchip identification standards with
the following statement from the same document: “. . . APHIS does not have the authority to
regulate private pet ownership or the retail sale of pets and consequently cannot mandate a
single national standard for the microchip identification of pets.”
The public comment period, which is part of the process of developing federal regulations, closed
on September 6, 2006, and a final rule is pending.
The preceding could lead someone to wonder why they should not simply have the 134.2 kHz
ISO FDX-B chip implanted in their pet. Or it could totally confuse them, since 125 kHz open
standard microchips are fully compliant with Annex A of ISO 11785. Does this mean that the final
APHIS regulation will accept the use of 125 kHz chips? Will APHIS rule making effectively
address the question of “universal scanners” or merely muddy the waters? Time alone will tell.
Standards like ISO, which do not have the force of law, are rarely implemented in the manner in
which they were written. At present ISO FDX-B transponders are hard to find for companion
animals in the United States. An attempt to introduce them several years ago failed because not
enough scanners were available to read the 134.2 kHz chips. It may take years to distribute
scanners with both 125 kHz and 134.2 kHz reading ability to all of the nation’s animal shelters,
just as it took years to distribute the “125kHz-only” scanners that are currently in use.
RFID microchips will work with whatever scanner can read them. The distribution of scanners
that can read the chip that you are considering is therefore the key to making an informed
decision regarding which type of transponder to select.
I chose to have my Red Fronted Macaw implanted with an open standard 125 kHz EuroChip
because these transponders can be read or detected by all 125 kHz scanners, in any country.
Since such transponders are considered to be ISO-A compliant, these chips can also be read by
fully ISO 11784/85 compliant scanners used to read the 134.2 KHz chips. Moreover, there
should be no compatibility problems with universal scanners if the 134.2kHz ISO-B transponders
are re-introduced into the US market. I considered using the functionally equivalent HomeAgain
chip, but chose the EuroChip because of the much larger number of birds identified in the
PetTrac database. I prepaid the fee for database registration when I purchased the chip. The
total came to about $20, which does not include the veterinarian's fee for injecting the chip.
I specifically avoided 134.2 kHz ISO-B transponders for two reasons:
1. Too few scanners are available in this country for these chips.
2. A potential problem exists with certain aspects of the ISO 11784/85 standard violating US
patent laws. This matter is not affected by how many groups or government agencies
support the use of such technology. Much of the technology used in the 125 kHz
domestic chips is the same as that used on 134.2 kHz chips. An attempt by a foreign
company to market 125 kHz transponders in the USA several years ago was defeated in
court by patent litigation. At least one of the US companies holding these patent rights
has indicated that they may litigate to protect their patents if 134.2 kHz ISO-B
transponders are re-introduced into the US market by foreign competitors. The court
concluded that the disputed US patents also covered 134.2 kHz ISO technology. I did
not want my parrot to be affected by the backwash of patent litigation, and therefore
chose to avoid 134.2KHz ISO-B technology.
The failure of the ISO Working Group to base the ISO 11784/85 “open” standards
around technology that is fully in the public domain may be one of the standard's most
serious flaws. For more about this, see “ISO 11784/85 "STANDARD" WITH BLEMISH”.
I considered using the 125 kHz encrypted chip because it is unclear how severe the problem of
duplicating tag numbers of open standard transponders will become. However, I wanted the
transponder to be easily readable on the remote chance that I might travel outside the country
with my parrot. Using a transponder from one of the two largest companies in the domestic RFID
market was a simple choice: I wanted my bird to be identified in a large, well established
database, by the most familiar technology. Just like the escaped prisoner running down Main
Street in an orange jump suit, my lost parrot should be noticed. I believe that if Flutters were to
fly away tomorrow, the chances of recovering him would be maximized. If he were to become
lost and escape predation, the chances of recovering him would not diminish over time because
he would have a permanent connection to me through his microchip. If he became lost 10 or 15
years from now, the chances of recovering him would be even greater because more scanners
will be available. It makes no difference if these are “125 kHz only”, or “125 kHz plus 134.2 kHz”
By having an RFID transponder implanted in him, I have greatly increased the odds of my parrot’s
recovery. However I am now cautious about watching old Star Trek TNG re-runs in his presence.
I'm not certain how I would react if my cyborg parrot were to suddenly say: "We are the Borg.
You will be assimilated. Resistance is futile."
Owners of smaller birds that have closed leg bands and are difficult to microchip because they
weigh less than 100 grams, can benefit from the lost animal database. These birds can be
registered in both of the largest national databases by their leg band numbers, thus allowing
shelters or veterinarians to easily locate their owners if the birds became lost. It is generally best
to register any animal with the largest databases.
It may be necessary to contact these databases by telephone at the numbers listed on their web
sites to initiate the registration process.
Status of Federal Regulatory Actions: Jan, 2007
APHIS has stated in Vol. 71 of the Federal Register that they are considering making a rule
requiring that dogs and cats covered under the Animal Welfare Act be required to be implanted
with ISO 11784 and 11785 compliant microchips. Without additional qualifiers, this implies that the
transponders must operate at a frequency of 134.2 kHz, and that the dogs and cats in question will
be those originating from the wholesale pet industry.
Presently over 99% of the RFID transponders used in this country operate at 125 kHz. The
overwhelming majority of scanners are also tuned to 125 kHz. Many of these 125 kHz chips used
in the USA are encrypted, while others are not. If APHIS follows through with their proposed rule
without adding any qualifiers, eventually the dogs and cats originating from the wholesale pet trade
will find their way into American homes. When that happens it will become necessary for
veterinarians and animal shelters to obtain scanners capable of reading RFID chips that
operate at both 125 kHz and 134.2 kHz. Additionally, these scanners must also be capable of
reading both encrypted and open format chips, or animals must be scanned up to three times with
APHIS has also stated in the the same volume of the Federal Register that they do not have the
authority to mandate a “single national standard for the microchip identification of pets.”
Therefore the United States will not be switching to the ISO standard for the identification
of pets at this time. There will simply be one more incompatible RFID chip on the market.
Congress attempted to address a perceived problem of scanner interoperability. The regulatory
response so far appears to be falling short of the mark.
Federal Rule Making Process:
Under the normal Federal Rule Making Process, the next time that the public hears of this issue
from APHIS will be when a final rule is published in the Federal Register. Final Rules are effective
30 days after being published in the Federal Register.
The following references concerning the development of the ISO 11784/11785 RFID standards are
made available to those who would like to inform themselves about the pros and the cons of these
standards. Technology embodied in these standards will be adopted to different degrees by
different national governments. In some parts of the world the free market may also decide to
what degree such standards will be adopted.
Index of Articles
The Controversial ISO 11784/11785 Standard: A Short Discussion
ISO 11784/85 "STANDARD" WITH BLEMISH
A discussion of the ISO standard for RFID: its provenance, feasibility and limitations
“In November 1998 a proposal: "Request for Suspension of ISO 11784 and ISO 11785 and their
return to WG3 for modification was disapproved by a majority of Australia, Belgium, Denmark
Finland, France, Germany, Ireland, Japan, Netherlands, New Zealand, Switzerland and UK. Votes
in favour of the proposal came from: Austria, Brazil, Canada, Chile, China, Czech Republic,
Hungary, Iceland, Italy, Romania, Russian Federation and Slovakia.”
The Controversial ISO 11784/11785 Standard:
International Standards Organization returns RFID standard for animal use to working
group for major revisions
The Controversial ISO 11784/11785 Standard:
ISO 11784/85 Update - WG3 meeting in Stockholm
Apparently the “major revisions” mentioned in the link above, were not implemented at the working
group level. The current ISO standards also are mentioned as falling short of Russia's national
requirements. Separate standards for livestock and companion animals were also never
“In the WG3 meeting in Malaga on May 3 and 4, 2001 it was concluded that:
Backward compatibility of 'ISO readers' for a period of 30 years as described in Annex A in
ISO11785 is an essential option to be provided by manufacturers of FDX-A technology.”
United States Microchip Report
“In the United States AVID sells an encrypted 125 kHz (chip), which means the microchip can
ONLY be read by AVID authorized readers.”
<<Note: 1. This article completely neglects to mention the existence of the AVID EuroChip – which
I had implanted into my parrot. This chip is functionally equivalent to the HomeAgain chip.
Note 2: See the link below this one for specific information about the capabilities of installed