Now you know why I keep Sulmet on hand. For some reason it gets a bad rap sometimes - and I"m not sure why. It's been of wonderful use here, and when you have something that's very vague, it does indeed treat more than one respiratory type illness. I believe you can even use it in conjunction with meds that treat MG. But I like your plan.
On the probiotics, you could use plain yogurt - it's cheaper. Heck you could technically use flavored in a bind - just try to strain the bigger bits out. I just recommend plain because I dont like a lot of sugar added or artificial flavors added, and I like to avoid the problem of people feeding pieces of fruit to birds who aren't eating grit. So I give the conservative answer: plain.. That might at least get them through the 7 days.
I'm very glad to hear that they're at least stabilized!!
On the disinfectant, the best one is supposed to be Oxine. It's one that you can actually use on the ground - but the ground does need time to rest for it to best work. But since you can mist the air with oxine, you can use it in their water (which I personally do NOT recommend as it's an antibacterial and our birds depend highly on their good bacteria), but it's safe enough for that - you can certainly use it all on the coops and ground.
And honestly, another great disinfectant is sunshine. But I'm assuming this is a permanent, not mobile, coop yes?
Here's an article that after going off on a bit of a tangent has some really great ways to use it. As for biofilm, I recommend organic apple cider vinegar instead. It adds beneficial bacteria, doesn't deter good bacteria, but will still keep the waterers free of biofilm and fresh smelling, and helps feed utilization as well as being a nice source of potassium in the summertime.
http://www.shagbarkbantams.com/oxine.htm
You can replace the bedding probably to good effect in the coop after this is done, or now and again after this is done
