Induced moulting procedures in laying fowl

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.