Chickens will ‘moult’ seasonally – usually, at the end of the summer, they will lose a lot of their old broken feathers and grow nice new ones. At other times of the year, chooks may have a partial-moult, where they lose some of their neck feathers. Both types of moult are completely natural and nothing to be worried about. It’s wise, however, to ensure that the bald patches aren’t due to an illness. Give your pets a thorough health check at the start of the moult.
Whilst most of the year, your chickens will look like this, they do go through several weeks of feather loss
During the moult, your hens will need to be provided with a very good diet. Growing all those feathers requires a lot of different nutrients, and so while they’re undergoing this process you may want to supplement their diet with some chicken vitamin supplements. Many chook owners have had success with Apple Cider Vinegar. It’s useful to understand that that during the moult, one resource that your chooks will need a lot of is protein. Don’t be surprised if your hens stop laying when they’re in moult. Feather production will use a lot of the protein that the hens get from their diet, so there may not be enough for egg creation.