Update: I started her on Rooster Booster the one with vitamins, electrolytes and probiotics and got the erythromycin because she can't wait until next week to get amox...it's the only antibiotic I could get right way, and it does seems to be a good one. I found a few post with dosing instructions, I think from
@Eggcessive and also this
http://www.poultrydvm.com/drugs/erythromycin according to this site it's approved by the FDA as safe for egg laying hens. just to be on the safe side if she does lay any in the next couple weeks (assuming she pulls through) I'll discard them. Definitely don't plan to consume her if she does not make it. I gave her first dose last night after flushing her out again with warm water (no more egg particles came out. Just prior to that we smelled a distinctive "rotten egg" almost ammonia like smell coming from her - it was FOUL. After a few flushes the smell was gone.
This morning she had poo in her litter for the first time (it was runny of course), seemed more alert and moving around, making some of her usual cooing noises. Her face is no longer bright red, her feathers are still fluffed but she doesn't appear to be in distress. She is eating and drinking well. No more nasty smells.
I'm going to prepare a saline solution to use for the next flush which will hopefully help prevent bacteria from growing while the meds do their job. I'll go ahead and order some fish mox to have on hand in case the EM doesn't work and just to have around for future emergencies where it may be the better choice. But she DOES seem to be improving from yesterday. Cautiously optimistic.