I am new to chickens and have a small flock of 7. One of the younger hens is now coming down with respiratory issues. She has bubbles in one of her eyes, which is now closed, her breathing is labored and she's wheezing and lethargic. I used Vet Rx, which I got from Aubuchon Hardware, but am not sure how effective it will be. Is there anything else I should be using? She's away from the rest of the flock now. Will this kill her?