Chickens on a broiler farm. Photo / Alan Gibson
Animal welfare advisers to Agriculture Minister David Carter say they are developing a separate code of welfare for the chickens used to breed "broilers" - the chickens which are killed at the age of six to eight weeks for meat production.
The National Animal Welfare Advisory Committee, which yesterday released
a new draft code for the broilers themselves, said there was a relationship between broiler genetics - such as selection of breeding lines for traits such as strong legs - and the health and welfare of broiler chickens.
Sophisticated genetic selection over the past 50 years has sent growth rates for meat chickens soaring, have increased by over 300 per cent, from 25g/day to 100g/day.
Overseas researchers have shown that rate of growth is a primary risk factor for lameness and poor leg health in meat chickens, and that selecting breeds for a high muscle-to-bone ratio may compromise their ability to walk.
In addition to lameness, rapid growth has been associated with bone defects and deformities - including birds known as "creepers", which have bone deformities - and with cardiovascular diseases, including sudden death syndrome where birds simply "flip over" and die.
"Broiler breeding companies are working to improve broiler leg and cardiovascular health," Nawac said today.
"A new code of welfare for broiler breeder chickens in New Zealand is currently under development and will address welfare in relation to breeding and genetic selection".
- NZPA
