Effect of Differing Temperature Cycles on Egg Shell Quality and Layer Performance

Egg shell quality deteriorates when the laying hen is exposed to high environmental temperatures. Within the continental United States, the normal spread during the summer months between the high and low temperature within a 24-hr period is 11 to 14 C degrees. Laying hens exposed to a 24-hr linear temperature cycle ranging from 26.7 to 35 C had a significantly poorer egg shell breaking strength, a thinner egg shell, and a significantly greater body-weight change than hens exposed to temperature cycles of 21.1 to 35 C and 15.6 to 35 C. No significant difference in performance existed in hens exposed to 24-hr linear temperature cycles of 21.1 to 35 C and 15.6 to 35 C. Use of ventilation fans at night reduces laying house temperatures to near the minimum daily temperature, which normally occurs just before sunrise.