The head of the National Animal Welfare Advisory Commitee says concerns about the genetics of poultry raised for eggs and meat won't be addressed for some time.
A new code for the welfare of chickens being raised for meat came into effect on Thursday.
John Hellstrom says work is in the very early stages for a code covering genetics and it may be a couple of years away.
He says the concerns relate to the intensive nature of poultry farming.
Mr Hellstrom says the rapid growth rates being promoted can lead to problems like lameness.
He says the industry in New Zealand is very integrated, and the breeding stock are imported from overseas, so the producers have very little influence over the birds they get.