I just started using Oxine without Citric Acid added, so not sure how well it works yet. But, it's a disinfectant for fungicidal, bactericidal and virucidal. It has demonstrated efficacy against these animal viruses: Avian Influenza A virus, PRRS Virus, Canine Parvovirus, Coxsackie Virus, Pseudorabies Virus, Newcastle Disease Virus, Foot and Mouth disease virus, swine Vesicular Disease Virus, African Swine Fever Virus.
It destroys odors too.
You can use it in a fogger. If you add Citric Acid to it, you have to remove all animals, food and water. You also have to use a regulated respirator mask ?? I can't remember which one, but it is a specific one.
I use it at 1/8 tsp per gallon in drinking water every other day. Helps keep bacteria down and slime down. I haven't had anymore pasty butt since I started putting it in their drinking water. May just be a coincidence.
Also, if I have a chick that does not look good I will use a fine mister and mist over the face so that they can breathe it into their air way. Helps kill the viruses and bacteria. I had a chick that kept falling over yesterday and I have misted his face twice now. Seems to be doing better, he hasn't fell over anymore, since last night.
I think anything is worth a try, esp if they are dieing.