Chicken is wheezing, drooling, comb is flopped over, eye is clouded over

[Uphilly]

Hello,
If anyone can help me that would be greatly appreciated. We have a Rhode Island Red who has been wheezing for about a week, so we bought some Duramycin 10 and have been putting it in the water. Today when I went to go let her out, she had drool running from her mouth onto her feathers, and she was wheezing and not moving quickly. I put down some scratch and when she walked over to get it, I noticed that her eye was clouded over and puffy and white, and she can't see out of it.
The other piece of relevant background: we added three pullets to our flock about three weeks ago, so we thought she was ill due to stress. This is a significant step in the wrong direction, though, and none of the other chickens seem to be ill.
I'm really afraid we're going to lose her. Any thoughts?
Thank you!

 

[Eggcessive]

Welcome to BYC. The chickens you added could have been carriers for mycoplasma (MG or CRD) or for coryza. Is there any bad odor from the sick chicken that may be from coryza? New chickens should always be quarantined for at least a month, and some will add one guinea pig chicken for an additional month just to see if it will become sick. Tylan 50 injectible is much stronger than Duramycin if you want to keep treating and not cull the sick bird. Dosage is 1 ml daily for 3 days. Separate each sick bird from the others. Here is some reading about some of the respiratory diseases: http://edis.ifas.ufl.edu/ps044