Quite a few weeks ago I had all 6 of my RIR cockerels come down with some weird neuro thing. At first I thought they had Marek's, but not infectious (they are housed with all the other chickens in one coop just separated by wire) They had been kept on pine shavings, were with the 3 three RIR pullets from the same hatch and the hen who hatched them, a BO. I noticed sudden weakness in legs, shaking, poor balance, poor condition (feathers dull and scruffy looking) and tails down. There was no diarrhea and the poop looked totally normal. THey ate fine and while the ones that were worst off improved slightly and eventually got their tails up again I eventually culled them all as they all still had poor balance and I doubt if they would have been able to mount a hen since they staggered everywhere and I was afraid to eat them. I never could figure out what on earth happened!? THere were the three pullets and the hen that went everywhere those cockerels went and they never showed any signs of ill health!!?? They have been on start and grow feed - same as other birds in the coop as well as the birds housed in their same enclosure, I tried all kinds of things to support like electrolytes, yoghurt, kefir and while they did perk up and look a little happier they really didn't improve otherwise. SO, the question is, what on earth do you think happened? I wondered for a while if they had got into some mouldy hay, then I thought maybe their waterer had some algae in, or maybe they ate some toxic leaves in the run, but the thing that is so confusing is that the other birds are all fine? And there was not a sign of infection with anyone in the rest of the coop or their enclosure. Only the RIR cockerels?! I have closed down that run for now but I am not sure if that is where the problem lay... but it is the only area where they went that none of the rest of the coop go.