This is a fantastic description of a broody hen: fluffed up and refusing to leave the nest box. She might also have a paler comb and, when she does go out for a quick snack and a drink, make a quiet, clucky sound, which is why another word for the condition is 'clucky'.
MadnessTo me, broodiness is like a kind of craziness has grasped the bird. She can think about nothing other than sitting on her eggs, keeping them warm. Whether they are actually fertile is neither here nor there to her. In fact, although eggs make her more likely to stay on the nest, she'll sit in there even after you've taken them away. By the time she's noticeably broody she'll have paused her own egg-laying and will be tucking the other hens' eggs under her warm belly, which has probably become fairly bald to allow skin-to-shell contact.
|Competition for space in the nest box.|
ChicksIt takes three weeks of incubation for chicken eggs to hatch, so your broody hen is likely to be in this state for a long time if you don't do anything about it. Without the stimulus of chicks appearing out of the eggs she may stay broody even longer. She'll get very thin, as incubating hens rarely eat.
If you want chicks, of course, broodiness is wonderful. You can buy fertile eggs cheaply off Trade Me, pop them under your hen, and in three weeks they'll probably hatch. A broody hen needs a quiet nest box to herself, and a safe place for her and her chicks (i.e. where cats, dogs and adult hens can't get to the chicks). They'll also need a water container that chicks can drink from but not drown in, and chick starter food. Having a mother hen and chicks is delightful.
If you don't want chicks, broodiness is a downright nuisance, and requires attention. It will be ongoing, too, because a hen that's prone to going broody will keep doing so again and again, even if you let her have chicks. She's valuable to people who want chicks, though, so you can easily sell her.
How to break broodinessThe most important thing is to keep her away from the nest. Some hens snap out of their broodiness more easily than others, and it may be a simple case of blocking off the nest box as soon as the other hens have laid, then unblocking it once darkness falls and all the birds are roosting.
|A failed attempt to block off the nest box|
More persistent brooders will just sit somewhere else, even if it doesn't resemble a nest. My most persistent one, a blue Orpington, once just sat in mud as the rain fell on her. She was completely gripped.
|A nicely constructed broody cage (in foreground)|
An alternative solution
Not having a broody cage, I recently came up with a different approach. I fenced off a paved area of our property well away from the coop, and put the broody in there, alone. She squawked terribly, and escaped repeatedly until I secured the fence properly. She was so distressed at being isolated in this way that she never sat down at all (this bird has a particularly reactive personality). At night I let her go back to her pals, and made sure she was on the perch at dusk. After three or so days of this treatment she snapped out of her broodiness.
A couple of weeks later, there she was, back in the nest box all day. Intolerant as I am of broodies, and greedy for eggs, I abandoned the fight and gave her away to someone who celebrated her broodiness and let her have chicks.
Choose your breeds carefully
Sometimes modern hybrid breeds like brown shavers go broody, but it's rare. The heavy, beautiful breeds that I love so much are the worst offenders, as are the delightful little Silkies. However, even within a breed there will be unpredictable variation: some individuals just do go broody, and some just won't even if you want them to. Such is nature, teaching us yet again that we cannot control her!
|Goodbye, pretty hen. You were too broody.|