Poultry: Moulting

The moult is a natural process where hens shed and renew their feathers. During the moulting period the reproductive physiology of the bird has a complete rest while the bird builds up its body reserves of nutrients, leading to a seasonal decline in egg production.

The provision of new feathers or a coat (a feature inherent in most animals) is a natural process, designed by nature to maintain a bird’s ability to escape enemies by flight and better protect against cold winter conditions.

Under normal conditions adult hens will moult once a year, in autumn. Some may moult twice in a single year or, more rarely, only once in two years. When a bird begins the moult depends on the time of the year she started laying. In most cases moulting should begin sometime during March or April, and egg production begin again around July.

Young pullets (chicks) will also moult, going through one complete and three partial moults during its growth to point of lay. Generally, the first, complete, moult will occur between 1 to 6 weeks of age. Partial moulting will take place at 7 to 9 weeks, 12 to 16 weeks and 20 to 22 weeks.

The three main factors that trigger moulting in poultry are:

  • Physical exhaustion and fatigue.
  • Completion of the laying cycle (birds can lay eggs only for a specific length of time).
  • Reduction in day length as winter approaches results in reduced feeding time and consequent loss of body weight.

What to watch for:

If a bird stops laying and moulting, it’s a sign that its physical condition is deteriorating, leaving it incapable of either egg production or the continued nourishment needed to produce feathers or maintain body condition. This is usually a sign of inadequate nutrition. During the moult the bird must still get a considerable amount of good quality food to replace feathers and build up condition.

For the backyard poultry keeper the date at which a laying hen stops producing eggs and goes into the moult is a reliable guide as to whether or not an individual hen is a good egg producer. Poor producing hens will moult early and take a long time to complete the process and resume laying, staying out of production for six to seven months. Poor producers seldom cast more than a few feathers at a time and rarely show bare patches.

High-producing hens on the other hand, moult late and for much shorter periods, around 12 weeks, and come back into production very quickly. A good layer will moult quickly, losing not only wing feathers but body feathers generally. A late and rapid moulting hen will often be practically devoid of feathers, with bare patches over its body.

Moulting takes place in a specific sequence. The first plumage is lost from the head and neck, then from the saddle, breast and abdomen (body), then from the wings and finally the tail feathers will drop.

When the first feathers drop from the neck and body, good layers often keep laying. However, when the wing feathers begin to drop, laying usually ceases.

Although it may look random to the inexperienced eye, feather loss occurs in a very specific and observable way. The main wing feathers consist of four tiny ‘finger’ feathers on the extreme tip of the wing, 10 large primary or ‘flight’ feathers, a small axial feather and 14 secondary feathers, which are smaller and softer than the primaries.

When the wing moults, the large primary feathers are shed first, from the axial outwards to the end of the wing. The number one primary feather is the first to drop, followed by a number two and then in order to number 10. While the primaries are shed, the secondaries begin to drop.

The axial feather drops at the same time as the secondary next to it. A new quill starts to grow as soon as the old feather is out, and takes approximately six to seven weeks to grow. The moult is complete when all primary flight feathers on the wing have been replaced. The feathers of bird in which the moult is complete are bigger, softer, cleaner and brighter than the old feathers, which would have been small, hard, dry and somewhat tattered.

The difference between a rapid and a slow moulter (or a good layer versus an indifferent layer) is not the differences in the growth rate of individual feathers, it’s the fact that a quick moulter can renew a large number of feathers at the same time. The backyard poultry keeper can use this to measure the rate of moulting by examining the number of flight feathers on the wing that are simultaneously being replaced. If a hen has grown some of her primaries before starting to lose her secondaries it indicates that she laid well into the moult and is therefore a good layer.

Most often, a layer will moult once egg production ceases, although, if the bird has an inherited tendency for high production, moulting will probably begin before she stops laying eggs.

If a hen ceases egg production for any reason other than mild sickness or broodiness, it loses its feathers. If a hen ceases production during spring or summer it may moult one or two primaries, stop moulting and come into lay again. A bird may also sometimes experience a neck or partial moult without any loss of production. However, if the moulting extends beyond the neck moult stage the hen ceases production.

Some birds may even moult continuously; these individuals are easily identified because of the spotless condition of their new feathers. Birds who moult this way are invariably poor producers and should be culled.

Stress factors and moulting:

Although the moult is a naturally occurring process, moults can also be triggered at any time if birds are subjected to stress. Any change in the flock’s environment or management can present birds with a challenge to which they cannot respond without harmful effects. A mild stress condition in late spring when in full production can trigger a drop in egg production. A hen subjected to the same stress condition in autumn will cease laying and moult.

Common stress factors that can induce moulting include disease, poor nutrition, extremes of temperature, poor housing, the presence of predators and poor flock management.

To ensure healthy birds and regular egg production you should aim to provide adequate housing, adequate nutrition and a balanced diet, access to the outdoors and continually rotating fresh forage.