I’ve always equated the word “broody” with “moody”, as in “brooding” over worrisome events. Now that I’ve read four or five books on chickens, I have a better understanding of the word, which is defined by Merriam-Webster as:
1 : being in a state of readiness to brood eggs that is characterized by cessation of laying and by marked changes in behavior and physiology <a broody hen>
According to www.feathersite.com, a broody hen is described as follows:
“A hen lays only one egg every day or two. She does not start to incubate them until the whole clutch is laid. This way all the chicks will hatch at the same time. The physiology of a hen changes after she’s laid her clutch. She will remain on them, with her wings slightly spread to help keep them warm, for 21 days. She will make muttering, growling sounds if disturbed, and may even peck or otherwise try to defend her nest. She will only leave the nest once a day to eat, drink and defecate. Once the chicks start to hatch she will remain on the nest with them for 24-48 hours. Any eggs that have not hatched by then will be left behind when she takes the chicks for their first walk. At this time water and chick feed should be available for the chicks…A hen is also called broody when she is raising her chicks, protecting them, teaching them to find food, and hovering over them to keep them warm.”
Broodiness has been bred out of many breeds in order to make them more productive layers. The Mediterranean breeds, such as Leghorns and Minorcas are among those that rarely, if ever “go broody”. Heavier breeds, like Brahmas and Australorps, as well as many bantams, are among the most broody of breeds. Silkies are known to be especially prone to broodiness and mothering chicks.
And here’s a video of a Silkie that adopted ducklings: http://www.youtube.com/watch?v=OEvkW0usaVA&feature=related