The Importance of Weight Control at Rearing in the Productive Aspects of Free-Range Hens

Abstract

Background and Objective: Alternative production systems have been welcomed and supported by consumers and egg producers. However, the classic free-range layer farming is a profitable business and suitable to produce egg and meat. The production performance of a layer is determined during the rearing phase. Thus, proper management is essential in order to achieve adequate weight and body composition at the beginning of the production phase so that the birds may reach the fullness of their genetic potential. In this sense, this study was conducted to evaluate the effect of the management on maintaining the weight uniformity of birds during rearing phase and on the production performance of laying hens. Materials and Methods: This study used the database of the Laboratory of Poultry Science, referring to Hy Line Brown^® chickens of the AVIUFSC Lot 018, raised during the period from March 28, 2019 to January 22, 2021. The obtained data were used to determine the growth curves until the end of the rearing phase. The data were also used for exploratory principal component analysis (PCA). Mean and variance of body weight per week per group in the rearing phase before and after the relocation was calculated. Results: Raising semi-heavy chickens without controlling weight uniformity during rearing phase produced lighter and more heterogeneous pullets. During rearing, grouping of pullets according to their weight produced more uniform and heavier pullets at transfer age. Heavier pullets become hens with higher egg production per week up to 49 weeks of age. Conclusion: Grouping of pullets according to weight during rearing phase produced more uniform and heavier pullets at transfer age.