Laying Hen Heat and Moisture Production under Commercial

Astudy was carried out with the objective of establishing heat and moisture loads in three commercial egg laying units in Alberta under winter conditions. The units studied were typical of triple-deck, deep-pit, and shallow-gutter, caged systems. Each unit was monitored for six 24-h periods over 4 mo. Adata acquisition system was used tocollect the data necessary to carry outa complete heat and moisture balance oneach unit. The total heat production rates of theWhite Leghorn layers ranged from 33.2 to 34.6 kJ/(h.bird) during the light period and from 24.9 to 31.0 kJ/(h.bird) during the dark period, the daily means ranging from 29.5 to 33.2 kJ/(h.bird) for the three barns. Moisture production rates ranged from 3.3 to 3.9 g/(g.bird) and from 2.6 to 2.7 g/(h.bird) during the light and dark periods, respectively, the daily means ranging from 3.1 to 3.3 g/(h.bird) for the three barns.