Today I noticed one of my white bresse looking not so good. This afternoon she was dead. We just buried her. There's a bit of hunching, ruffled feathers, weight loss, loss of appetite *even the muscovies*. It's been very wet with the snow melt off. The chicken vet said it sounds like an upper respiratory infection and we're treating with injected tylan right now. Do we just dose with 1 time injection? I'm assuming treat absolutely every flock member, what about the ducks?