need advice on latest ill chicken- sour crop or worms????

[chicken stress]

Well, where do I start. Started out with 6 rhode island red/leghorn cross hens 2 years ago as pullets. One got taken by a coyote while free ranging next to our house....learned my lesson. One had what I assume was a pendulus crop from the day we got her, fought sour crop with her for months, vomiting her, feeding her yogurt, scrambled eggs, olive oil, no luck, she passed. That was a year ago. This spring, the snow melt left a couple of inches of water sitting in my chicken run for weeks. I knew it wasn't good hygiene and did all I could to clear it up, replace dirt, move them to a temporary shelter etc. Finally got them back in and coop settled when my daughter noticed roundworms in one of their poop. I tried to keep them as organic as possible and had not wormed them, so I read up and wormed them with Wazine first, then Ivermec about 10days later, followed later by electrolytes in the water a few days later for about a week. Well, the one with the worms in her poop went downhill. She just sat puffed out, stopped eating/drinking, lost weight, was skin and bones in the end. Despite our best efforts to force feed her yogurt, buttermilk, scrambled egg with a syringe and water/electrolytes, she died the other day. My daughter was distraught, it was her favorite chicken. I figured that the bird had such a bad case of worms that it did intestinal damage. Well, to say the least I am paranoid now. I am down to 3 girls, 2 look great, moving around well, alert, good color and eating/drinking well. The only thing I notice wrong with them, is some liquidy poop (not all of it, some is firm) and drinking a lot. The other is still a nice fat bird, but has got definite sour crop the last few days, very little liquidy poop. She is leaking sour fluid from her beak, and I have vomited some of it out several days in a row. Started her on Monistat as I read on this forum, feed her yogurt, buttermilk and fluid. Only other symptom is that she has a darker red crop than the other girls and it is a bit drooped over. She sits still most of the day, bright eyed will move if urged, not really eating or drinking on her own, only what I have given her today. I can't lose another chicken! I read that the loose poop, sour crop, drinking a lot may be worms, so I just treated them all again with the Ivermec, this is about a month after the initial treatment, figuring that the first treatment didn't get them all. Any ideas what is going on with my girls, no vets around here take chickens.
Stressed is an understatement, I am dreaming about chicken illness! My daughter is beside herself with the thought of losing another.