The document examines how acute stress and alternative feeding strategies affect fault bar development in broiler breeder feathers. It finds that acute stress induces more moderate fault bars in wing feathers. Control birds subjected to daily feeding restriction have more fault bars than those given alternative diets or non-daily feeding frequencies, indicating these strategies may help reduce stress. The number of fault bars does not differ between juvenile and induced feathers, but induced feathers have more moderate bars, showing fault bar development reflects stress levels.

1. Does feed restriction lead to fault bar
development in broiler breeders?
Arrazola A., Mosco E., Widowski T.M., Guerin M.T. and Torrey S.

2. Fault bars in feathers
 Definition
Feather malformations generated during
feather growth resulting in a translucent
line perpendicular to the rachis (King and
Murphy, 1984; Jovani and Rohwer, 2016)
 Caused by psychological stress
Fault bars in a broiler
breeder tail feather

3. Development of fault bars
 Mechanism
1) Musculature contraction
2) Blood pressure
Fault bar and intact barbs in chicken wing
feathers microscopically observed at 2.5x
Fault bar formation
due to lag on protein
deposition Feo and Prum, 2014

4. The development of fault bars in feathers
Affected by malnutrition, age, sex, disease, CORT
and habitat (Jovani and Rohwer, 2016)
Has been correlated with:
Low survival (Bortolotti et al., 2002)
Handling in wild birds (Murphy et al., 1988)
Feed restriction (Whitmore and Marzluff, 1998)
Parasite infection (Møller et al., 1996)
Fault bars in wing
feathers at day 3

5. Development of fault bars
Induced wing feathers in European starlings
(Sturnus vulgaris)
Strochlic and Romero, 2007
P=0.08Induced
feathers

6. Development of fault bars
Wing feathers in white stork
(Ciconia ciconia)
Jovani and Blas, 2004

7. Objective
The objective of this research was to examine the effect
of acute stress in broiler breeders on the development
of fault bars in feathers

8. Hypothesis
We hypothesized that the birds under acute stress protocol
will have a higher number of fault bars, and the number of
fault bars should mimic the number of stressful events

9. Experimental design, housing and management
30 Ross 308 broiler breeder
pullets located to 6 cages
2 Treatments: control and
unpredictable stress protocol
Unpredictable stress protocol:
Physical restriction (20 minutes)
Crowding (2 hours)
Feeding delayed (2-3 hours)
Repeated twice (week 3-6)
ControlStress
A
A
A
Week 3
Week 6
A
A
BW
BW
Feather
collection

10. Feather analysis
Six feathers per bird
(wing, tail and scapular)
Number and length of fault bars
o acute fault bars: < 5 mm
o moderate fault bars: ≥ 5 mm
Initial number of fault bars for
the wing feather
Feather mass and length
Tail
(R1)
Scapular
(Sc3)
Wing
(P8)

11. Statistical analysis
Generalized linear mixed model
Cage nested in the model as
experimental unit
Feather type analyzed
independently
Cage location as random effect
P<0.05
Tail
(R1)
Scapular
(Sc3)
Wing
(P8)

12. The effect of stress on fault bars development
*
Fault bars in wing
feathers at day 3
P<0.05(*)
P<0.01(**)
Initial**
Initial x stress*

13. Conclusion
The development of fault bars was affected by the type of
feather, tail feathers had a higher number than scapular or
wing feathers
Acute stress induced the development of moderate fault bars,
but only in wing feathers
The total number of fault bars in wing feathers increased in
birds more susceptible to develop fault bars before the acute
stress started

14. Broiler breeder paradox
Control growth rate
Feed restriction (> 43% )
2175 g at week 5
2195 g at week 20Mortality
Health
Reproduction

15. Commercial feed restriction programs
Hunger
Lack of
satiety
Frustration
 Feather pecking
 Object pecking
 Overdrinking
Feed
restriction
Feed
allotment
Competition
Feeding rate
BW uniformity

16. Alternative feeding strategies
 Reduce feed quality
Addition of fibre
Appetite suppressants
 Intermittent feeding frequencies
Skip-a-day
4/3
5/2
Graduated
36 pullets at week 12

17. Objective
The objective of this research was to examine the
effect of an alternative diet and non-daily feeding
frequencies for broiler breeders on the development
of fault bars in wing feathers

18. Hypothesis
We hypothesized that the daily feeding treatment that
provided the largest feed allotment, the alternative diet,
will have the lowest number of fault bars compared to
control and non-daily feeding treatments

19. Experimental design, housing and management
1,680 Ross 308 broiler breeders 70 pullets/pen (7.7 birds/m2)
24 pen in 4 rooms
4 isocaloric dietary treatments
From 3 to 22 weeks

20. Dietary rearing treatments
Appetite suppresant + 40% Fibre
1. Control diet. daily
3. Control diet. 4/3
4. Control diet. graduated
2. Alternative diet. daily

21. Feather analysis
Two wing feathers per bird from 10
birds per pen (juvenile and induced)
The juvenile feather was plucked at
week 15, and the induced feather
grew from week 19 to 21
Number and length of fault bars
o Acute fault bars: < 5 mm
o Moderate fault bars: ≥ 5 mm
Feather mass and length
Juvenile (P8) Induced (P8)

22. Statistical analysis
Generalized linear mixed model
Pen nested in the model as
experimental unit
Feather type was included as a
repeated measure
Pen location and room as
random effects
P<0.05 Juvenile Induced

23. The effect of feeding strategy on fault bar development
Juvenile feather Induced feather
P<0.05(*)
P<0.01(**)
Control > 3 others*
Control > non-daily feeding**
Juvenile Induced

24. Conclusion
The number of fault bars did not differ between juvenile and
induced feathers, but induced feather had a higher number of
moderate fault bars than juvenile
The number of fault bars was higher in the control compared to
the three alternative feeding strategies, especially among non-
daily feeding restriction
*****
The lower number of fault bars in alternative feeding strategies
compared to control can indicate that these strategies helped to
reduce the birds’ susceptibility to acute stress

25. The effect of feeding strategies
This conclusion is consistent with results of:
 Feeding motivation test
 The frequency of stereotypic behaviour
 Feather coverage
 Reproductive success

26. Acknowledgements
Advisor
Dr. Stephanie Torrey
Advisory committee
Dr. Tina Widowski
Dr. Alexandra Harlander
Dr. Michele Guerin
Dr. Elijah Kiarie
Students
& Volunteers
Animal Behaviour
and Welfare Group
Arkell Poultry
Research Station
staff

27. Intra-observer reliability (adjusted R2)
Feather
Primary Rectrix Scapular Total
Type of fault
bar
Acute 60.69% 46.79% 37.70% 56.99%
Moderate 77.63% 80.27% 83.89% 96.89%
Both 73.19% 95.13% 55.91% 96.37%