EFFECTS OF BODY-WEIGHT AND FEED RESTRICTION ON THE PRODUCTIVE EFFICIENCY OF LAYING HENS

A study to evaluate the productive efficiency in egg-laving hens was c arried out with body weight and feed restriction being the determining factors. 150 Warren-ISA hens were divided into three groups at 11 wee ks of age: 1) 850-950 g; 2) 1000-1100 g; 3) 1150-1250 g. In thier thir teenth week two further subgroups were formed: a) hens on feed restric tion; b) hens fed ad libitum. Factors compared in the six subgroups we re body weight, feed consumption, percentage of egg production, egg sh ell weight, egg shell dry matter, feed conversion efficiency and biolo gical efficiency. The results show that body weight varied among the ' six subgroups during the experiment but that there were no significant differences in egg production among the 3 weight groups. When fed ad libitum the third group produced heavier eggs than those of the other two groups, but it consumed more feed and the feed conversion efficien cy was reduced. When feed restriction is considered, however, eggs of uniform quality and quantity were produced in all 3 groups.