Study on the Suitable Environmental Temperature and Humidity for Hy-line Brown Layer Breeders in Summer

PurposeTo investigate the appropriate environmental temperature and humidity in summer for Hy-line brown layer breeders.

MethodsIn 6 henhouses with environmental control system, we recorded the room temperature and humidity from June to August, the body mass, age of first laying, egg production, number of broken eggs and total number of eggs of 30000 Hy-line brown layer breeders from 0 to 26 weeks, the hatching performance of 180000 parental breeders and the egg quality of 60 eggs at the age of 200 days, calculated the daily average temperature, humidity, temperature-humidity index (THI), uniformity of body mass and coefficient of variation and analyzed the suitable THI range for breeders.

ResultsThe daily average temperature, humidity and THI from June to August were 22.07-30.51 ℃, 61.88%-93.20%, and 70.70-82.46, respectively. The body weight and uniformity of chickens can reach the standard at the brooding and finishing periods. The age at first laying was 140 days. Within the age of 220 days, the average laying rate, broken egg rate, fertilized egg rate, hatching rate, and healthy hatching rate were 93.93%, 0.50%, 94.49%, 91.20%, and 92.51%, respectively. Indoor temperature and THI were significantly positively correlated with laying rate (P<0.01), while humidity was positively correlated with laying rate and total number of eggs (P<0.01). Temperature, humidity, and THI were negatively correlated with breaking egg rate (P<0.01). The results of 200-day old egg quality analysis indicated that the average egg weight, eggshell strength, eggshell thickness, egg shape index, yolk color, yolk ratio, and Haugh unit were 59.21 g, 5.45 kg/cm², 0.39 mm, 1.28, 7.58, 27.78% and 80.42, respectively.

ConclusionsIn summer, the growth and development, hatchability performance and egg quality of Hy-line brown layer breeders were good in the environment with THI from 70.70 to 82.46.