I have noticed over the past couple days that my OEG bantam rooster has been walking slowly/wobbley, almost hobbling along, and he likes to just lay down most of the time, instead of pecking around like the rest of the chickens. He doesn't even try to keep up with the flock, so he is alone most of the time. I tried catching him today and he kicked up his speed maybe one gear, but nothing like he normally does. No change in feed or bedding, free range during the day. Any ideas? Injury? Disease? Old age?