The more I read, starting to think non-med....

[chickenjen]

Sounds like to me they are getting into something they should not be. It could be a number of things. Is there a chance that at some point (previous resident?) rat poison was used in the barn? It could be something from another animal that their little systems just can not handle?

I am no chicken expert but those are my basic observations. Maybe try slowly increasing their "range" so there is less of a change from a small area to the whole barn. Then you could possibly figure it out a little easier.

 

[prairiepearls]

It's important to know there's not just one "magic bullet" that does the trick for everything, like medicated feed, or immunizations, or something to boost their immune systems. None of those will protect against all possible problems, because various problems can be caused by bacterial infections, viruses, genetic defects, injury, fungal infections, etc. It's just like with people -- antibiotics won't cure a viral or fungal infection, Tamiflu won't do a thing if you have a bacterial sinus infection, and there's no immunization for athlete's foot. Boosting your immune system in general is probably always a good idea, but it can't protect you from direct exposure to a strong germ. I think the posters are right who are suggesting you find out exactly what's wrong with them before spending any more money or time on what might be the wrong cure. I'd post on the Diseases & Emergencies forum with a detailed description of their symptoms, feed, living conditions, age, etc. (there's a list of questions to answer in that forum to help others diagnose your problem). Good luck to you!