Early growth and brooding management
Skeletal defects such as varus/valgus deformities and kinky back (spondylolisthesis) are exacerbated when a producer cannot either control early growth rates or create conditions that derivate in very uneven flock early in life. These conditions are uneven brooding temperatures in the house, excessive cold or hot litter temperatures, cold draught, not enough feed space or water availability, or not enough light. Any of these uncomfortable conditions for broilers during brooding reduce their early feed intake and physical activity and both affect leg bones, muscles and tendon development.
It is important that broilers reach at 7 days of age body weights that are four times their initial body weight. This means that the average body weight should be between 160 – 180 grams (average 0.37 lbs) at the end of the first week. Flock uniformity can be measured by the coefficient of variance (CV %) of the population obtained with data of individual body weights. This value should not be higher than 10% during the first week of life. However, it is not unusual to observe flocks with average body weights lower than 145 grams, or several individuals in the flock with 100 grams or less and 200 grams or more. Under these circumstances, the CV is 14% or higher. In this type of uneven flocks with individuals that have rapid early growth is common to observe leg problems later on in life.