I have a male bantam Sussex chick that is about 8 weeks old..was fine yesterday...went in today and found this one very sick...one was dead as well...both were fine yesterday and I came home to this one laying down and having problems breathing...vomiting...not able to stay sitting up...dead chick was about 5 days old...and I have another one that is three days old exhibiting the same symptoms..the 8 week old chick was not in the same pen as the two smaller ones....any help is appreciated..I tried to attach a video but it says it is too large....