Horrific cases of chickens who have been rescued from battery farms. Chickens who are subjected to the stresses of living in densely packed cages quite often pluck their feathers out. (Some battery farms engage in the equally horrific practice of “debeaking” their chickens to prevent this).
When chickens are rescued from these environments they are often suffering from a huge number of ailments, including the absence of large patches of feathers, which cause them to be not only chilly, but uncomfortable and prone to picking at themselves when new feathers grow in. A couple of years ago some rescue groups released patterns to make sweaters for these rescue chickens, and a trend began. (Presumably the same logic would apply to aiding chickens who have been inexplicably rendered featherless by tornadoes, but that’s another story.)