It might not be a bad idea to get some copper sulfate to put in the water for a while. (It will turn the water blue and kills off bacteria and algae too.) A little goes a very long way, and during the summer months I always add it to at least one of the water containers here. Copper sulfate not only provides copper supplement to the chickens, which often helps alleviate egg shell problems, but also kills a whole host of bacterium, viruses, etc. I use 1/2 TBSP per 5 gallon community water container.
Copper sulfate is also a fantastic soaking treatment for bumblefoot or other lesions, and can be applied directly to a wound prior to bandaging. It's another one of those old school, old-timer farmer's secrets. I believe you can get it at tractor supply.
Thank you!