Induced moulting procedures in laying fowl

Abstract

Several successful methods of inducing moulting have been used to recycle laying hens, the majority of which require an optimum weight loss of 25–30% to achieve maximum egg production during the post-moulting period. The conventional feed restriction procedure is most often used in the egg industry because it is a simple, practical and economical technique that can be used in combination with light and/or water restriction. Mineral-induced moulting procedures, such as the use of high levels of either aluminium in the form of a soluble salt or dietary zinc, have also been used successfully. In addition, low levels of dietary zinc combined with a low calcium diet have also induced moulting in laying hens. The use of low sodium diets has been equally as successful as the conventional feed restriction technique as a means of inducing a moult. Although mineral-induced moulting procedures produce similar results to the conventional feed restriction techniques in post-moulting egg production, but with lower mortality rates, some of these procedures may not yet be practical for use in the egg industry. Hormone-induced moulting is another method and involves the use of the gonadotropin-releasing hormone (Gn-RH) agonist. It has an advantage over the conventional feed restriction procedure in that it does not require severe initial body weight loss to attain maximum egg production in the post-moulting period.

Keywords:

• Induced moulting
• feed restriction
• minerals
• hormones
• laying hens