Dang - So sorry you have to go through this. But I am astounded that you caught it so early - most catch it after it is well developed and difficult to control. You'll have a better chance of success since it was caught early. I am still checking on whether you have to hold back the eggs. Good question. Wait until we can get confirmation on this. I'll get back or maybe someone else can get in here too.
It is good that you isolated her, but the others may have been exposed also. For this, copper sulfate is generally used as a preventative.http://www.mcmurrayhatchery.com/acidified_copper_sulfate.html That is not to say they will get it, but from reading the posts most will use it once a month just to make sure. What I did, since I felt my newbies had been exposed, was I ordered something called Berimax and I gave it to the pullets at 12 weeks of age for 5 days. I thought they would hate it, I tasted it and it tasted terrible. They thought it was kool-aid! No problems with them drinking it and haven't seen any indications in any of my girls so far. If you want more info on that let me know. On the FishZole I wanted to tell you, I tried hiding it in a piece of moist bread. The first one she just gobbled up. Tried it the 2nd day, she didn't get the whole dose b/c she refused it. Maybe she had learned that I was trying to trick her I don't know. I did discover that the pill dissolves quite quickly and will just disappear and you cannot tell how much they ate. I remember having to run back in the house, split one and go back out and put it down her throat to make sure she got the full dose. So she probably got more than she was supposed to. After that, I just took an eyedropper and cup of water, put the pill in her mouth as far back as I could, then gave her some drops of water. That turned out to be the easiest. As I said, FishZole has a wide safety margin, but the normal dose for a standard is one 250mg pill once a day. If you are concerned about spreading the dose, you could split it and give 1/2 of the pill two times a day. As far as sanitizing, the bug lives best in water, it needs moist conditions. So it spreads easiest through their water or if a bird has it and drools or picks up a piece of food, tongues it and drops it, then another one picks it up right after, now it has been exposed. So anything moist, it doesn't do well when exposed to the elements.
I'll check on the withdrawal period for the eggs for you.