During the first four days of their lives (the brooding period), chicks are unable to regulate their own body temperature. Their proper growth and development therefore depends on the climate that poultry farmers create for them. Achieving the perfect combination of air and floor temperatures, air velocity and humidity levels that lead to superior chick quality can be quite difficult. If these variables are not exactly right, the result is delayed chick start-up, lower uniformity and uncertainty about future growth curves.