Looks like Scaly Leg Mites?
The scales on the legs of healthy chickens are smooth and lie flat. If you notice the scales on your chicken's legs starting to peel up, flake or look rough and uneven, she could be suffering from scaly leg mites.
Scaly leg mites are a type of external parasite that can bother chickens by burrowing up under the scales on their legs and feet, causing the scales to become crusty and lift up instead of laying flat and smooth. Normally, providing a clean, dry environment and dust bath area will keep parasites at bay, but if you see evidence of leg mites, there are various ways to get rid of them naturally. Scaly leg mites spread from hen to hen, so it's best to treat them all if you notice one having issues. The mites are too small to see with the naked eye, so the raised leg scales will likely be your only visual clue. Initially the mites merely cause discomfort, but if not treated and allowed to fester, can cause the chicken be in poor health (and therefore susceptible to other issues) to go lame, be unable to roost, and eventually even cause death. Feathered leg breeds are more susceptible.
-Soak the legs and feet in warm water and a mild dish soap, then rise and dry them off.
- Using an old toothbrush, gently scrub the afflicted hen's legs and feet with white vinegar, garlic juice or Neem Oil.
- Apply some olive oil or even plain coconut oil or Green Goo. This will help to smother the mites and suffocate them. (Green Goo contains herbs to help soothe and heal as well, so that would be my #1 choice.)
Repeat the treatment every other day or so, until the old scales fall off and nice new, shiny, smooth scales regrow. This can take a matter of weeks to several months for severe cases.
It's a good idea to clean out your coop at the same time, since the mites can burrow down into the floor and like to live in damp conditions. After cleaning out the old litter, I recommend spraying the coop walls and floor down with white vinegar or spray, then sprinkling food-grade Diatomaceous Earth on the floor and in the nesting boxes. DE helps kill all kinds of insects and parasites without harm to you or your chickens.
- Provide a dust bath area for your flock filled with dirt or sand, DE and some insect-repelling herbs such as lavender, lemon grass, thyme and wormwood. This should allow your chickens to keep all kinds of parasites at bay themselves.
-Consider putting down some vinyl flooring on the floor of your coop to prevent mites from burrowing into the wood.