I have seen a backyard chicken, a laying hen, approximately 5 years old. She has had a 3-month history of thick crusty scabs on both legs and feet, approximately 0.5cm thick. Trying to remove the scabs leaves exposed flesh. The peripheral edges of the scabs are yellow. The chicken's activity has reduced and she is not laying. The lesions are not in the right place for bumblefoot. It doesn't look like any scaly leg I've seen but I guess it still could be. Her feet have been bandaged daily. She will still perch occasionally. The scabs initially looked infected so were treated with tylan and manuka honey but now are dry. Unfortunately I don't think I can attach pictures to this message? Any advice on differentials and treatment options would be greatly appreciated!
I would be highly suspicious of chronic scaly leg mite. As soon as the leg scales are damaged and compromised their growth is altered and fails. Treat as if you would a wound that is healing by secondary intention. I would also consider using Dergall to treat the mites as this will not irritate bare areas, make a solution and dip the entire leg in it once a day for 3-5 days. Alternatively you can smoother the leg in Vaseline which will suffocate mites present or Ivermectin drops if eggs are not consumed.