I have 20 cornish cross and one died, it was not doing well last night. I noticed it panting and not wanting to move around much. it also did not want to eat. I seperated it from the others and today it was dead... I noticed some of the others maybe 3 also panting. I left the coop for a bit and when I came back they had calmed down and seem ok. I know usualy you loose some of the birds but this seems early to me. do you think something is wrong?