I have 5 chickens, 2 buffs,a welsummer, light sussex and lavender pekin, also lavender pekin cockrel. All within a week's difference in age as bought at week old. All others ok but one buff is lame and staggery, as if she is drunk. She eats fine, drinks fine and poohs fine. She runs around when I let her out and flaps and flies, but cant corner or she falls over, also seems to rock back a bit on legs to balance. She has had it for about a week, maybe was slightly lame first the week before but not obviously. They are in a 9 bird coops uk coop with extra run section and I let them out for a bit every day too. Fed on novagrow, corn and scraps. Lots of veg and fruit. She doesnt seem to be unhappy and is getting no worse so havent seen a vet yet. I have looked online but cant find any obvious answers. Anyone have any ideas?