I'm not sure what's wrong but 2 of my 6 leghorns have died in the last week. I think another will be gone by tonight. I have one now that won't come out of the coop and is having a hard time walking. She falls forward and sits down. It's the same thing the other two did before they passed. I'm thinking maybe it's worms? I've been adding Apple Cider Vinegar to their water but now I'm looking for Valbezen and having a hard time finding it. On-line is takes 2 weeks. Any ideas what could happening? I'm heartbroken.