I have a leghorn hen that was exposed to a new chicken recently. Within a few days she got pretty sick - lethargic, nasal discharge, losing some feathers. Thought she was gone at one point actually but she appears to be on the mend. Treated with antibiotics and electrolytes. Going to worm them just in case and also treated the new hen the same even though she showed no I'll signs. Wondering if they'll continue to be carriers and need to be culled or isolated or can they eventually join a larger flock this spring?
Birds that are survivors of respiratory diseases are always carriers. Stress will bring out symptoms, treated or not...like introducing them to your main flock. If you eventually introduce them to your larger flock, you risk exposing your flock to whatever disease you're dealing with.
