My eight month old light brahma rooster has had a sore leg, I thought, until I picked him up to look. It appears that both middle toenails are gone, kind of rough, scraggly looking parts, but very short, obviously no nail. Is there a deficiency of some sort? All the birds free range, lots of dirt, grass. The floor of their home is cement. I am also wondering if the cement may have worn them off, but that seems rather remote. He is only in there for a few hours during the night time, released early in the day. Have a great day.