Hi folks - sad news I'm afraid, Minnie didn't make it. She was so weak, she just started panting a few minutes after tube feeding this morning, couldn't keep it up, gasped a few times and that was it.
Sybil has been doing much better, she's gained a little weight, and is eating normal chick feed, preening, and keen to join the other chooks. Still keeping a close eye on her - she's panting a bit every now and then (vet mentioned passing the dead worms can be a bit stressful for them), and her poop still has quite a few (hopefully dead) oocysts in.
Thanks everyone for your help!