What is a broody hen
A broody or clucky hen is one that has decided to nest and hatch a clutch of eggs. It is an instinct that is triggered by hormones, but can be set off by not collecting eggs regularly or seeing another broody hen in the nest.
They will stubbornly sit on the nest refusing to get off and often peck and growl at you if you try and remove them. If you do take her off she will cluck around and run back to the nest at her first opportunity.
A broody chicken will fluff itself up and sometimes pull the feathers from its breast to feather the nest and expose its skin to warm the eggs it is sitting on.
Some breeds are more inclined to go broody than others which is great if you want to hatch a batch of fertile eggs but if you don't it is best to break the cycle, and the sooner you start the better.
Once a Chicken sits on a group of eggs she releases a hormone called prolactin which suspends egg laying temporarily. She will sit on the eggs for the next 21 days until they hatch then resume laying about 5 weeks after that. However if they are not sitting on eggs they can carry on sitting far longer than 21 days so you can be left with no eggs for up to 3 months.
What can you do to prevent them going broody
Some breeds are more predisposed to broodiness than others, like bantams that tend to go broody after every ten eggs or so, but there are some things you can do to discourage them.
Seeing a clutch of uncollected eggs or other broody hens can encourage hens to go clucky so collect your eggs regularly and remove any hens from the flock as soon as you notice any signs of broodiness.
How to break a broody hen
To break a broody hen you need to cool down her breast and remove her from her comfy nest.
I personally like to place the clucky hen in a wire bottomed cage for a couple of days then return to the coop and watch for further signs of broodiness. If she still exhibits signs or returns to the nest I place her back in the cage for another day then try again,
This works by allowing air to circulate around under the bird and cool her belly and breast down.
I've heard people recommend all sorts of ways to break them including ice baths, or leaving them suspended in water troughs etc, but consider these cruel and inhumane so do not practice, recommend or encourage them.
Why break a broody hen
When a hen goes broody she will stubbornly sit in her nest, eggs or no eggs and only leave the nest now and again to eat drink and poop.
She will ignore her own health in anticipation of her chicks and will loose weight and condition,, she also increases her chance of getting parasites like white mite as she is not out dust bathing.
Other birds are encouraged to go broody as well and you will not get any eggs for the entire time she is broody plus about 5 weeks after.