My silver-laced wyandotte hen I just bought from a poultry swap last week has sunburn on her back from lack of feathers. Her pinfeathers are coming in fine, and she seems to be in overall good health. I've used aloe vera on her back to treat the existing sunburn, but after awhile in the sun her back still looks red and inflamed. What kind of sunblock can I use to protect my poor bird's back? Thank you for any assistance in this area.