In chickens molting and treading marks are the most common reasons for feather loss. Both conditions are perfectly natural and usually require no human intervention.
About once a year chickens go through a molt. Molting is the time that a chicken will shed their old feathers and grow new ones. It is a completely natural occurrence and takes anywhere from 5 – 12 weeks to complete.
Molting usually follows a period of heavy egg production and hens will not lay eggs at all or will lay eggs sporadically during their molt. Laying hens usually fall into two groups -late molters and early molters.
Hens known as late molters will lay eggs on average for 12 to 14 months before they begin to molt.
Late molters are generally the better laying hens and they will often have a more raggedy and tattered appearance during their molt.
Hens known as early molters sometimes begin to molt after only a few of months of egg production.
Early molters take longer to complete their molt and are often poor layers. They can have a fuller feathered appearance and don’t look as moth eaten. They often will only shed a few feathers at a time.
Fall is the traditional time of year that the molt occurs due to a decrease in daylight. During the molt period feathers are lost in a predictable sequence. Feathers are lost from the head first, followed by those on the neck, the breast, the body, the wings, and then lastly the tail.
One thing interesting about one of the hens in the photo below is that she has an unusual loss of feathers across her back. Below I’ve enlarge a portion of the image and added an arrow so you can see it better.
The loss of feathers on her back is from more than just molting. It’s called a treading mark.
She has a treading mark because she was a favorite with my main rooster and some of the other young roosters. During copulation or mating (called treading in chickens) the rooster’s feet sometimes will tear feathers from the hen’s back as he moves his feet quickly across her back while he is on top of her.
The above hen has been treaded so often that she now has a very big bare spot on her back. She has had it since the summer and in fact looked quite bad until just recently.
Her feathers will probably grow back in time if she can manage to stay away from the rooster.