ok i have 60 8 week old chicks and they are of various breeds I went out to check on them in the coop last evening and there were 2 dead....i had the heat lamps on them and it was raining out i have lost a few before the rain too but they are dry all closed into the coop and i went out to do my morning routines and there were 6 more dead.....no blood in poop......the ones that are not dead are all most all standing up and not looking good.....i gave them some vita chick water to see if that helps any but i really need help before something happens to all of them, could this be mareks or worms pneumonia i need help please....there are with my 12 and 13 week old birds too....all the older ones seem fine but do i need to take the younger ones away in case of disease ......... PLEASE HELP..THANK YOU