You should read this thread before you decide to cull:Did you ever figure out what it was?
My flock is seriously infected at the moment. I'm leaning toward coryza. Either way, I'm thinking of just culling all and taking a break from chickens for a year. I've been dealing with a mystery predator and now this. I'll just clean the coop really well reinforce the run (possibly enlarge it) and just not worry about it til next summer.
My question is, if we do cull, is the meat ok to eat?
https://www.backyardchickens.com/t/888717/respiratory-problem
-Kathy