NUTRITION ▶▶▶


Importance of feather cover in broilers


BY STEVE LEESON, PROFESSOR EMERITUS, UNIVERSITY OF GUELPH F


eather growth begins at day 5 of incubation, ap- pearing in distinct tracts that cover at most 75% of the skin surface. By 40 days of age, broilers will have about 50 grams (g) of feathers remaining after some


prior juvenile sequential moulting. During early incubation, skin cells start to form into ‘lines’ that will eventually be- come feather tracts visible to the naked eye by day 9. The germ bends posteriorly as it grows so ensuring that the feather will be contoured to the body. Abnormal position- ing of feathers (e.g. helicopter wings) may be caused by em- bryonic follicles in the wing failing to orient themselves at around day 8 of incubation. Shortly after hatch, the sheath of each feather dries and


As market age for broilers continues to decline, the ‘maturity’ of feather cover becomes increasingly important for protection of the skin and underlying tissue.


flakes away becoming the main contributor to the hatch- tray debris. There is compelling evidence that incubation conditions can have a major impact on feather growth and appearance. Work conducted by Novus International Inc. some years ago, clearly showed that early ‘heat-stress’ of the embryo causes retarded feathering. Such overheating of young embryos was more common with multi-stage setters, where eggs are necessarily loaded into very warm ma- chines. With more modern single-stage setters any over-


Contrary to popu lar belief, the feathers do not grow ran- domly or uni- formly over the entire skin sur- face but rather in distinct tracts.


▶ POULTRY WORLD | No. 8, 2021


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PHOTO: LEX SALVERDA


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