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  5. What is induced moulting of layer hens?
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What is induced moulting of layer hens?

Induced moulting in the poultry industry involves artificially forcing hens to moult through manipulating their environment and diet to replicate the natural process of moulting that occurs seasonally in wild birds. This process involves total feed deprivation and/or severe feed restriction for several days to weeks. RSPCA Australia opposes all methods of induced moulting.

Induced moulting is most commonly done at the end of a hen’s first laying cycle to improve the productivity and quality of eggs in the following laying cycle.

What is induced moulting?

Moulting in birds is a natural physiological process which involves the periodic shedding and replacement of feathers, as well as the stop of egg laying and resetting the birds’ reproductive system to prepare a bird for the next laying cycle. This naturally occurs seasonally coinciding with egg incubation and the brooding of chicks in wild birds [1].

In a commercial setting, hens are housed in controlled environments with constant temperature and lighting. Therefore, the seasonal influences that once naturally induced moulting have been removed.

Moulting has been traditionally induced through total feed and/or water withdrawal programs for several days as well as reducing the photoperiod (day length) to that of natural day length or less. Another method being more commonly used is non-feed withdrawal programs which involves the severe dietary restriction of only 40-60g /day per bird of a low nutrient or specific mineral diet (low calcium or sodium diets, high zinc or iodine diets) for several weeks. Both these methods aim to cause dramatic body weight loss (up to 30% of total body weight) in hens to stop egg production and cause resetting of the reproductive system to induce the moulting process.

The Australian Model Code of Practice for Domestic Poultry 4th edition currently allows birds to be deprived of feed and water for up to 24 hours and unlimited days on a restricted diet of 40-60gm/day per bird to induce moulting [2].

What are the animal welfare concerns with induced moulting?

The current processes for induced moulting completely disregard one of the most basic standards of good animal welfare: to provide good nutrition by ready access to fresh water and a diet to maintain full health and vigour. During normal production, layer hens are fed at least 100g/day per bird. The inadequate feed, whether through total deprivation or severe restriction, causes rapid and significant loss of body weight, which is a clear indication that hens’ nutritional needs are not being met.

During induced moulting, hens have been shown to demonstrate clear behavioural changes including stereotypic behaviours (head shaking, bobbing and pacing) which indicate that an animal is distressed [3]. Hens have also been found to be more aggressive with increased pecking and cannibalism of other hens regardless of the method used to induce moulting [4].

Is induced moulting allowed in the RSPCA Approved Farming Scheme Standards for layer hens?

The RSPCA Approved Farming Scheme at present covers the production of eggs, pork, chicken, turkey, salmon and dairy veal. The RSPCA’s standard for layer hens aims to improve the welfare of layer hens producing eggs in Australia. This is done by ensuring RSPCA Approved farms provide their hens with nests, perches, litter to dust and bathe, and enough space to move around. The RSPCA standard does not permit any methods (feed withdrawal or non-feed withdrawal) of induced moulting to be used in RSPCA Approved layer hen farms.

References

[1] Berry WD (2003) The physiology of induced molting. Poultry Science 82:971-980.

[2] The Australian Model Code of Practice for Domestic Poultry 4th edition (2001).

[3] Shimmura T, Eguchi Y, Uetake U et al (2008) Comparison of behavior, physical condition and performance of laying hens in four molting methods. Animal Science Journal 79:129-138.

[4] McCowan B, Schrader J, DiLorenzo AM et al (2006) Effects of Induced Molting on the Well-Being of Egg-Laying Hens. Journal of Applied Animal Welfare Science 9:9-23.

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Updated on September 27, 2019
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https://kb.rspca.org.au/knowledge-base/what-is-induced-moulting-of-layer-hens/

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