Thank you for your suggestions. I will pick that up tomorrow and give it a try. It's obviously not necrotic dermatitis, which was the one idea the vet had, as she's still alive and well. I didn't do a skin biopsy as we were trying the antibiotic first. Honestly, I just can't spend a lot more money trying to figure out what this mystery disease is, so I don't think I can go down the biopsy route. Plus the poultry vet is 40 minutes away, and it was such a stressful journey for Penny! Maybe that sounds bad, but we've already been financially stressed for a couple years due to great lengths we went to for our dog, who didn't make it in the end. These decisions are really hard to make.