Hi! I have a female black call duck that has been turning rather white. I got her last summer at an auction and I do not know her age. Any ideas??? But, I'll get to the point. She has been limping a little. One day she'll be limping and the other day she'll have no sign of a limp. She acts perfectly normal eating her layer, rolled oats, flock raiser, and daily treat of grass. Is it possibly she could have a hint of arthritis in her hip, leg, and/or foot??? When she limps, it's just a little one, but sometimes it's like a tiny collapse, but she get right back up. Any ideas???? Thanks!!