I have a mixed flock: RIRs, barnevelders, amuericanas, Easter eggers, etc. A couple months ago, we noticed a stop in egg production when two of our hens went broody, didn't think much of it, because this has happened in the past. Fast forward to about two weeks ago, we have now lost over half our flock. There are no signs of trauma, they are fed and watered, they are in a coop that is large and enclosed. We have sand as the bedding. If they are sick, do we let this run it's course? Or do we kill the remaining 4 (out of 14), and do a major disinfect and start fresh? We've lost chickens in the past due to obvious trauma, but never anything like this.