Intensive / Monitoring Body Weights
Monitoring Body Weights
Body Weights should be monitored weekly during the growing period and until after peak. At least 100 birds should be weighed individually with a scale having increments no larger than 20 grams. Weighing should be started at two weeks of age and continued every week during the growing period until after peak.
It is most critical to weigh just prior to a scheduled feed change. If the flock is below target body weight it should be left on the higher nutrient feed formulation until the target weight for age is reached.
In addition to body weight averages, the uniformity of body weights within the flock is an indicator of normal flock development. Uniformity is expressed as the percent of individual weights which occur within 10% of the current flock average. A realistic goal is for 80% uniformity.
Factors which can adversely affect body weight and uniformity are crowding, disease, poor beak trimming and inadequate nutrient intake. Weighing at frequent intervals will determine the age at which a flock is deviating from normal and thereby help identify the problem so that corrective measures can be taken.
Variability Between Individual Birds Within A Flock
Uniformity of individual birds is important as well as appropriate average flock weights. A desirable goal is for 80% of birds to fall within 10% of the mean. That is, if the average flock weight at 18 weeks is 1500 grams, 80% of all birds should weigh between 1350 and 1650 grams. Graph individual bird weights to be sure there is a bell shaped or “normal” distribution as shown below. To evaluate uniformity, at least 100 birds should be weighed.