Commercial broilers are chickens raised for meat production through selective breeding over generations. Main breeding lines are crossed to create grandparent, parent, and commercial broiler lines with desired traits like increased growth rate and feed efficiency. The first commercial meat crosses in the 1930s used Cornish and Plymouth Rock breeds. Subsequent genetic selection improved production traits but also unintentionally caused issues like reduced fertility and health problems in fast-growing modern lines.

1. COMMERCIAL BROILER DEVELOPMENT
Mainlines
•PEDIGREE
• AA BB CC
DD
Mainlines
•GREAT GRAND
PARENTS
•AA BB CC DD
First crosses
•GRAND PARENTS
•AB CD
Crossparents
• PARENTS
• AB CD
Four-way cross
• BROILERS
• ABCD
 Any chicken mainly used for meat purpose,
 Slaughter weight (7-14 weeks)
 First attempt for meat production cross breed was in 1930 cross
between Cornish strain(male: double breasted) and Plymouth rocks
(female: tall, large boned)
 intense genetic selection for economically important traits including
body weight, growth rate, feed efficiency, and ultimately traits
associated with carcass-processing characteristics
 Although these improvements have come with some unintended results
(reduced reproductive performance, skeletal abnormalities, ascites,
and increased abdominal fat),