The objective of this study was to determine a model for crude protein requirements (CP) for laying hen by the factorial method. The protein maintenance requirement was determine by the nitrogen balance technique . The crude protein requirement for weight gain was determined based on body nitrogen content and nitrogen efficiency for body deposition. The crude protein requirement for egg production was determined based on the nitrogen content of eggs and nitrogen efficiency for egg deposition. Considering the requirements for maintenance, egg production and weight gain, it was elaborated a protein requirement model for laying hen: PB = 1.94xW.75 + 0.480xG + 0,301x E, where PB = requirement (g/bird/day), W = body weight (kg), G = daily weight gain (g/day) and E = egg mass (g/bird/day).
crude protein requirement; factorial method; laying hen; requirement model
