My rooster has been walking stiff legged for a long time since he was young. He also doesn't stand for very long and plops down in the middle of eating. More recently he hasn't been quite stable on uneven terrain. He still crows, eats, and drinks but is struggling with his mobility. I feel he should have been paralyzed by now if it was Mareks. He developed the walking funny over a year ago and dismissed it as just a goofy quirk. Any ideas? Thank you