Not Always a Pretty site...
During autumn, many household poultry keepers, particularly people
keeping poultry for the first time, are puzzled because egg production
markedly declines or ceases despite their laying birds appearing
healthy. This seasonal decline in egg production occurs when birds go
into a condition known as the 'moult'.
Moulting is the process of shedding and renewing feathers. During the
moult, the reproductive physiology of the bird has a complete rest from
laying and the bird builds up its body reserves of nutrients.
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 usual conditions, adult birds moult once a year. Some may moult twice in one year and, rarely, once in two years.
The pullet
The chick goes through one complete and three partial moults during
its growth to point of lay. Generally, complete moulting occurs from 1-6
weeks of ag, and partial moulting at 7-9 weeks, 12-16 weeks and 20-22
weeks. During this final moult, the stiff tail feathers grow.
The laying hen
Mature birds normally undergo one complete moult a year, usually in
autumn. However, this can depend on the time of the year that the bird
started laying. Natural moulting usually begins sometime during March or
April and should be completed by July when egg production recommences.
The three main factors that bring about moulting are:
- physical exhaustion and fatigue
- completion of the laying cycle (as birds lay eggs for a certain period of time)
- reduction of the day length, resulting in reduced feeding time and consequent loss of body weight.
Eleven months of continuous production is expected from pullets
hatched in season. So if a flock of pullets commences laying in March at
six months of age, they should continue laying until the following
February, although an occasional bird may moult after laying for a few
weeks. However, these few birds should begin laying again after June 22
(the shortest day of the year) and continue in production until the
following autumn. Pullets coming into lay in June should lay until the
following April, giving 11 months of continuous egg production without
the aid of artificial light. Pullets coming into lay in spring (August)
should lay well into April (nine months); however, unless artificial
lighting is provided, most of them will moult during May and June.
Moulting and nutrition
If a bird stops laying and moulting, this means its physical
condition is deteriorating and, therefore, cannot support egg
production, continued nourishment of their feathers or body maintenance.
Feathers contain protein and are more easily grown when laying ceases
because of the difficulty in assimilating sufficient protein for both
egg and feather production. During the moult, the fowl still needs a
considerable amount of good quality food to replace feathers and build
up condition.
Good layers and moulting
The time at which a laying hen ceases production and goes into moult
is a reliable guide as to whether or not the hen is a good egg producer.
Poor producing hens moult early (November-December), and take a long
time to complete the process and resume laying i.e. they 'hang' in the
moult and are 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 moult late and for a short period (no more than
12 weeks), and come back into production very quickly. Rapid moulting is
seen not only in the wing feathers of good producers, but also in the
loss of body feathers generally. Because of this, it is common to see a
late and rapid moulting hen practically devoid of feathers and showing
many bare patches over its body.
The moulting process
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- Figure 1. The moulting process
Moulting takes place in a particular order. Feathers are confined to
definite tracts or areas of the body surface, with bare patches of skin
between. The first plumage is lost from the head and neck, then from the
saddle, breast and abdomen (body), then from the wings and finally from
the tail.
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.
The main wing feathers comprise 4 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, primary feathers are shed first from the axial
outwards to the end of the wing. Then the secondaries are shed, though
not in such a set order as the primaries. 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 the moulted bird are larger, fuller, softer, cleaner, brighter and
glossier than the previous feathers, which were small, hard, dry, frayed
and tattered.
The difference between a rapid and slow moulter is not a difference
in the growth rate of the individual feather, but the fact that the
rapid moulter renews a large number of feathers at the same time. With
this knowledge, the rate of moulting can be ascertained by examining the
number of flight feathers on the wing being replaced simultaneously. If
a hen is found to have grown some of her primaries before starting to
moult her secondaries, it may be assumed that she laid well into the
moult and was therefore a good layer.
Sometimes, high producing hens do not moult all their primary
feathers but carry them on for another year. Generally, a layer moults
when production ceases; although, if the bird has an inherited tendency
for high production, moulting will probably precede cessation of
production, and conversely if she is a poor producer. Modern laying
breeds should moult in late autumn because they have been bred
specifically for egg production, i.e. to lay at a higher rate and for a
longer period of time.
A laying bird that lays regularly usually retains old feathers. If a
hen ceases 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 and then stop moulting, and come into lay again. This
is known as a vacation moult. When the hen starts its full moult later
in autumn, it drops the next feather in sequence and moults in order of
the remaining primaries.
A bird may 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.
The presence of 'pin' feathers (new emerging feathers) usually indicates a short or partial moult.
Some birds moult continuously and can be easily detected in the flock
by the spotless condition of their new feathers. These birds are poor
producers and should be culled.
Stress factors and moulting
Natural moults can occur any time of the year if birds are subjected
to stress. A bird becomes stressed when the environment or management
presents a challenge to which the bird cannot respond without suffering a
harmful effect. If a hen is subjected to a mild stress condition in
late spring when in full production, she will suffer a drop in egg
production; whereas, if a hen is subjected to the same stress condition
in autumn, it will cease laying and moult.
Common stress factors that can induce moulting include disease,
temperature extremes, poor nutrition, predators and poor management.
These are discussed in more detail in a separate article (see Further
reading below).
Production and moulting
After moulting, birds in their second year of egg production will
produce 10-30 per cent less than in their first year of lay, as the lay
rate is lower and the birds cease to lay earlier in the following
autumn. Birds that have moulted twice and are laying for their third
year produce only 70-80 per cent of their second year's eggs (about 60
per cent of their first year's production).
Moulting cockerels
Cockerels also moult and, while in this condition, are nearly always
infertile because they have lost weight and their reproductive
physiology is in a resting phase. Care must be taken to ensure that
cockerels do not lose more than 25 per cent of their body weight while
moulting, as this can lead to sterility.
Advantages and disadvantages
The four main advantages of keeping hens during the moult and the following year are that:
- it is cheaper to carry a bird through a moult than buy replacement pullets
- fewer replacement pullets may be needed and buying can often be deferred, which means saving money, time and transport
- moulted birds are hardier and not as prone to disease
- only high-producing, efficient birds will be retained if strict culling is undertaken during the first year.
The main disadvantage of keeping the hens is that, although moulted
birds eat less feed than pullets, they lay less eggs. Overall, their
conversion of feed into eggs - and feed cost per dozen eggs - is higher.
Other disadvantages are that:
- during the moult, they continue to eat but remain unproductive
- they are not as tender to eat if they are slaughtered for the table after two years of laying
- too few birds may be retained to provide sufficient eggs the following year.
Year-round laying and moulting
Year-round egg production can be achieved through the purchase of
pullets in autumn at point-of-lay. This provides sufficient eggs while
the older birds are moulting. When the pullets' rate of lay declines in
the summer, the additional eggs from the moulted birds should sustain an
adequate supply. The following autumn, the older birds can be
slaughtered for the table, the best pullets can be allowed to moult, and
another lot of pullets on point-of-lay can be purchased. This allows
for 20 per cent pullet wastage due to deaths and culling. Only 70 per
cent of the normal pullet requirements need to be purchased and, at the
same time, a relatively constant year-round supply of eggs is
guaranteed.