21 21 LOHMANN TIERZUCHT › MANAGEMENT GUIDE Growing pullets change their plum- age several times. There can sometimes be a slight de- crease in the body weight develop- ment at this stage as the attention moves to re-feathering. Feathering Uniformity Uniformity can be used as a tool to demonstrate whether all birds within the flock have been supplied with an equal amount of equally nutritious feed, it also helps to predict the lay- ing performance of a reared flock. The highest uniformity can gener- ally be observed at the age of 15–16 weeks. There can sometimes be a slight drop in the uniformity levels at this point due to the onset of sexual maturity. However, having a good average body weight leading up to this point will limit any impact. › Stocking density › Feed structure (avoiding selective feed intake) › Trough length and height › Availability of water › Stress factors (diseases, vaccination) › Age of the flock when uniformity is measured › Weighing method: the more birds you weigh, the more accurate the calculated uniformity will be › Movement and management within the system Calculation examples Body weight & Uniformity Stage 3 The final stage is usually completed by 16 weeks of age. There will be a complete change of plumage where the flight feathers will have been replaced. Stage 1 Replacing the day old down with the first full coat. Usually completed by 5 weeks of age. Stage 2 Around 8 to 9 weeks a further re-feathering will occur. An increase in feathers on the floor will be seen. Wings of pullet at about 18 weeks of age A poor development of feather growth at 13 weeks is often an indicator of inadequate weight development and/ or lack of flock uniformity. If this oc- curs then it should be addressed as a matter of urgency. › Check body weights and uniformity › Check feed and water – quality and consumptions › Look for viral or bacterial infec- tions (coccidiosis is a common cause of growth depressions) Factors which influence flock uniformity: