When Chickens Moult
My hens have stopped laying and there are feathers everywhere. Is there something wrong?
If you have horses, or long-haried pets, you will be all too familiar with ‘moulting’ (molting). That dreaded spring event that gets everything covered with hair but results in a gleaming new summer coat underneath. This process is most marked in breeds that have evolved in temperate areas where there is marked variation between the winter and summer climates. Like Shetland ponies and red deer. Most of these animals also go through an autumn moult which is less obvious.
But did you know that chickens also shed their feathers and grow new ones on a regular cycle. This is controlled by changes in hormones and chickens will go ‘off-the-lay’ during molting. Losing old feathers and growing new ones is energy demanding and can be uncomfortable for the birds so they need to be provided with space, grace and high protein feed.
Annual Moult
For normal, healthy hens, the trigger for annual molting is decreasing daylength in the Autumn (Fall). This is accompanied by a halt to egg production and takes between 4 and 12 weeks (average 7-8 weeks) Chickens in their first 12 to 18 months will not go through this molt during their first or second autumn and will continue to lay. This will depend on when the chicks were hatched.
Artificial lighting can be used to manipulate molting and drop in egg production, but for free range, pasture raised hens like ours, we need to do what we can to care for our hens during this natural cycle.
Hens will look rather scruffy during the moult as the old feathers are released and slowly fall out.
Daylight and hormones
Egg production and seasonal changes are both regulated by hormones and these change in response to daylight in seasonal breeding animals and birds. Hens are long day breeders. Meaning that they breed during months with longer daylight and stop breeding when the daylight decreases. This makes sense from a survival perspective as it would be less favourable to raise chicks in the middle of winter when it is colder and food sources are potentially limited. Some animals such as sheep, goats and deer are short day breeders. Their reproductive hormones increase during autumn. This is because they have a gestation of 5 months (sheep and goats) or 7 1/2 months (red deer) and breeding in the autumn will result in giving birth in the spring or summer when the weather is warmer and feed is plentiful.
For the Hen, when daylight is long, during summer, there is both inhibitory and stimulatory effects on the hypothalamus and the release of a hormone called gonadotrophin releasing hormone (GnRH). The stimulatory effects are greater than the inhibitory effects so the hens continue to breed and lay. When daylight declines in Autumn, the inhibitory effects become greater than the stimulatory effects and egg production ceases. Around the shortest day, effects become equal again and then as daylength starts to increase, the stimulatory effects are considerably greater than inhibitory resulting in the greatest egg production activity in the spring.
Further Reading
Sharp P (1993) Photoperiodic control of reproduction in the domestic hen. Poultry Science 72(5) 897-905
Here is a page with a lot of information and pictures on all things related to chickens https://the-chicken-chick.com/molting-what-is-it-and-how-to-help/
This page gives in depth detail of reproduction in chickens. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7153309/
Overview of the genetic and hormonal control of egg production https://www.intechopen.com/chapters/66081
Thompson, M (2014) Bird Academy - Everything you need to know about feathers
