I was wondering if cockerels develop at a different pace in certain areas and if there could be a nutritional deficiency causing my 13 week old roos to start staggering and lose their balance, become weak?? I had 6 RIR cockerels that had no other symptoms aside from weakness, poor balance and high stepping gait. Despite a month of attempts to correct whatever was going on, I eventually had to cull them. Now I have a totally unrelated roo, also 13 weeks old, in a totally different area of the property just without warning is too weak to stand for longer than a few seconds. He seems to have a good appetite, poop is normal - I really can't see anything else out of the ordinary. They are all on start and grow mash (same as a bunch of other chicks) with kelp meal and DE added. He and a number of pullets are in a chicken tractor that is moved to 'new' grazing (not much now in the winter) every other day or whenever the grass is getting too low. It has been really wet for about a week but none of the birds look wet, although they are not roosting yet. I have put some hay in under a heat lamp so they can lie down on something other than wet ground... A friend said that thiamine deficiency in goats (or maybe sheep I don't remember) can cause similar symptoms. That made me think that maybe this is not illness and could be remedied with some kind of supplement? Who knows about this stuff? Any ideas folks?