The effect of beak-trimming, strain and housing conditions on the development of brown pullets during rearing

In a trial with 8 x 510 pullers, half of the animals were beak-trimmed by h ot cut on dap 1. Birds were kept in two different aviary systems of four un its each. Half of the pullers were Isa-brown hybrids and the other half Loh mann-brown animals, respectively. During the 17-week experiment, beak trimming was followed by a minor reduct ion in body weight for the first two weeks, which disappeared during the re maining trial. Beak trimming resulted in a non-significant reduction of cum ulated food consumption by 10 to 20 grams per bird. This also resulted in a slightly better feed conversion rate (FCR) for beak-trimmed pullers. The b ody weight of Lohmann-brown animals was significantly increased by 5 to 7% compared to Isa-brown pullers. On the other side, a decrease in food consum ption by 2 to 5% was observed for the Isa-brown hybrids. Because this reduc tion could not compensate for the lower body weight, FCR was not significan tly better for the Lohmann-brown strain. In relation to the housing conditi ons, differences were detected for body weight and food consumption. Differ ences in mortality were mainly caused by accidents up to week 2. Beak trimm ing did nor influence mortality. A mathematical model was used which allows to predict the body weight durin g the growth phase of rearing pullers.