PURPOSE: To increase the productivity of eggs and improve the growth of chickens and the survival ratio to laying hens by uniformly controlling the temperature of each chicken cage at respective optimum level.

CONSTITUTION: A plurality of chicken cages 12 partitioned with partition walls 11 are connected in a row in the longitudinal direction of a chicken house. Each chicken cage 12 is provided with chicken-holding cages 15, 16. A forced ventilation apparatus 34 composed of a set of a medium-diameter fan 31, a large-diameter fan 32 and a small-diameter fan 33 is connected to the exhaustion port 18 at the rear end of the chicken house at a position corresponding to each row of the chicken cages 12. The operation of each fan 31,32,33 is switched by a controller 35 according to the room temperature, etc., of each cage 12.