Induced Moulting—A Review of the Literature, Current Practice and Areas for Further Research

SummaryThe literature on induced moulting is extensive and recent; however, most of the work is concerned only with commercial egg production from the domestic fowl (38 references are listed). The majority of the evidence indicates that stocking policies involving induced moulting are the most profitable.Low egg prices, large differences in price between the weight, grades and high livestock depreciation costs all favour the moulting policy. There are indications that moulting can be the safest financial proposition in a market where egg prices fluctuate unpredictably.Stocking policies involving moulting have a lower average working capital requirement than pullet policies, a fact which most authors fail to take into account. Moulting, therefore, shows an increased economic benefit above that so far indicated in the literature.The average egg weight and shell strength is greater with moulted flocks. Some papers also report improved internal egg quality (Haugh unit score)—one report a reduction. The methods of inducing a moult include one or more of the following in various combinations: drugs, feed deprivation and restriction, water deprivation and restriction, light restriction (short day length), low calcium and low sodium diets. A valid comparison of the different methods is not possible; however, in the author's experience most commercially used methods include all of the above except drugs.The data comparing one moult with two or three moults are inconsistent, but it seems that several moults may be practicable in certain economic circumstances.The data of classes of stock other than the domestic fowl are for the most part concerned with breeding turkeys where moulting is shown to be a practical method of increasing the productive life.Details are given of areas where further research is required.