I think my poults have Coryza but not sure. I’ve tried to talk to the vet but he’s not a big chicken person. They have the swollen face and the gasp for air and it’s contagious. I have about 15 in quarantine. I gave them LA 200 two days ago and put the vet RX on nostrils and combs but still not better. Can’t get Tylan 50 without a prescription so wondering if Duramycin will work? If so how much per poult? The laying chickens still haven’t got it yet so I’m kinda curious to why on that any help would be appreciated