Young broiler chicks need ambient heat to control their body temperature. The required ambient temperature depends, among other things, on the bodyweight of the day-old chicks. Their bodyweight can be influenced by the age of the breeders, where older breeders can bring forth heavier chicks.
During six production cycles, the effect of two different temperature gradients on the mortality of lighter chicks (breeding eggs from younger breeders-3 cycles) and more heavy chicks (breeding eggs from older breeders-3 cycles) was investigated.
Two identical broiler houses were heated the same way (32°C). After bird placement, one house followed the higher temperature schedule, the other house followed the lower one. There was a difference of 2°C between the two schedules only during the first 10 days.
The mortality of the heavier chicks was not influenced by a different temperature gradient during the first 10 days. The lighter chicks, however, showed a significant difference in mortality between the two groups.
The higher ambient temperature during the first 10 days resulted in a lower mortality on day 14 and day 36 resp. 1.91% and 3.99% compared with the chicks who experienced a lower temperature in the beginning and which showed a higher mortality of 2.50% at day 14 and 5.33% at day 36.
This experiment concludes that the mortality of lighter chicks can be strongly influenced by a difference in ambient temperature during the first 10 days of the production cycle.
Source: K. De Baere, J. Löffel, J. Zoons, I. Kempen, E. Vervaet, J. Nys Provincial Centre for Applied Poultry Research of the province of Antwerp, Geel, Belgium
Proceedings of XIVth European Poultry Conference, June 2014, Stavanger, Norway