I am shocked at how well these have hatched. There re 10 out now with 4 left to go and one of those has pipped!!!
I have never treated scaly leg mites in chickens, but have in canaries and other finches. I used SCALEX on them and it worked well, but can be labor intensive. A lot of mites can be opportunistic and will explode in population if there is stress. That can be changes n weather, breeding, raising babies, nutritional...pretty much any stress. Soak the legs/feet is warm soapy water and scrub them gently with a vegetable or toothbrush. It will soften the scales and loosen the mite debris. Then you can paint on the Scalex and completely cover the legs/feet. I can't recall the length of treatment, but it should be reapplied at least every couple of days...more often if they are dust bathing. There is a bit of a recovery period even after the mites are dead while the inflammation resides.