Implications of changes to commercial broiler and broiler breeder body weight targets over the past 30 years

Broiler breeder hens grow more efficiently and are leaner than ever before due to positive results from broiler genetic selection strategies. Quantitative feed restriction is used to limit excessive weight gain and maximize egg production and fertility. Over the past 30 years, broiler breeder body weight (BW) targets have undergone change, although the degree of change is small compared to the large increases in growth potential. As a result, the degree of feed restriction needed to maintain broiler breeder BW targets has increased, which is a welfare concern. The objective of this study was to examine current and historical broiler breeder BW targets for three major broiler companies to assess the extent of changes in BW targets over time and to explore potential reasoning behind shifts in these growth targets. By comparing breeder parent target BW profiles with corresponding potential broiler growth, changes in the apparent severity of feed restriction of the broiler breeder of this strain were calculated. Factors affecting the interpretation of degree of restriction values were discussed in combination with current initiatives underway to alleviate the severity of feed restriction. This information is intended to demonstrate how management of broiler breeder stocks has changed in time and to provide context for a realistic measure of the degree of feed restriction in broiler breeders.