Impact of hatchery microclimate, breeder age and storage time on egg water loss in a tropical climate

This study aimed to evaluate the effects of incubator microclimate, broiler breeder age, and fertile egg storage duration on egg water loss in a commercial hatchery within a tropical climate. Data were collected from the environments (air-conditioned egg room and incubator) in order to perform microclimatic assessments, in which temperature (T; °C), relative humidity (RH; %) and specific enthalpy (h; kJ.kg of dry air^- 1) were recorded at 10-minute intervals. Twelve Logen microprocessors were used in the egg room and one microprocessor was assigned for every three treatments in the incubators. Water loss in fertile eggs was verified using eggs from three different ages of Cobb Fast breeders (young = 29-30 weeks, intermediate = 42-43 weeks, and old = 52-53 weeks), from the same flock and analyzed over time. Twelve storage time ranges were also analyzed (87-103, 174-184, 196-208, 244-255, 63-77, 150-160, 172-184, 220-231, 40-57, 128-137, 150-161 and 198-208 h). In each treatment (combining breeder age and storage time), 35 individual eggs were weighed, totaling 1,440 eggs. Weighing was conducted upon entry and exit from both the egg storage room and the incubator using a semi-analytical balance. The experimental design used was hierarchical, in which the storage times are nested within the ages of the broiler breeders, with 35 replicates. T, RH, and h in the egg room and incubator showed higher averages during summer (p < 0.0001), and remained outside the recommended thermal and enthalpy ranges across all seasons under tropical conditions. The highest water loss of fertile eggs in the egg room and incubator was observed in eggs from older breeders (p < 0.0001) and under longer storage periods (p < 0.0001), particularly at 244-255, 220-231, and 198-208 h. Under tropical conditions, the T and h of the egg room and incubator are not within the ideal ranges in the studied seasons. Eggs from old breeders and those with longer storage times were those which presented the greatest water loss values. These findings highlight the need for improved environmental control in hatchery facilities under tropical conditions, particularly through tighter regulation of temperature and humidity and by minimizing egg storage duration, especially for eggs from older breeders, in order to reduce excessive water loss and optimize incubation performance.