Old English Game bantam hen, very sudden onset, appears to be respiratory illness. She is wheezing/gasping with each breath, head and neck thrown back with beak open. Gave her injection of 1/4 cc Tylan 50 about an hour ago but did not get it all in (First time giving a shot). We had another chicken with a respiratory illness last week, she cleared up after 3 days/3 shots Tylan, but that one didn't have the wheezing and gasping. I will take her to the vet in the morning, but I'm worried about her making it through the night since it seems like she is struggling to get air. Is there anything else I can do right now? (We have a flock of 18, but this particular chicken is a very special pet). Can she last the night in this state? Thank you for any help.