Yikes! Poor Zack. Pixie's troubles started with coccidiosis too. The vet gave us something for it, I can't remember what though. She got a little better, but the vet diagnosed her with mild colitis. It seemed all the medicines made things worse, so the vet and I decided on a more natural course.
No food for a day, then boiled chicken and white rice for a few days. Then gradually trying out foods for 1 that would agree with her. It was a tough time... the gradual switching over of foods (over 5 days each time) then a few days (if that) on just the new food...then back to totally runny poos. Followed by a day of no food, then back to chicken and rice for a few days...then gradually introducing another new food. We ended up with Eukanuba Natural Lamb and Rice puppy formula. Maybe not the best food, but she tolerated it fairly well until we switched to an adult food, Wellness 5 in 1 chicken, and eventually a 50/50 mix of Wellness and Evo.
Has your vet recommended a 1 day fast, then boiled chicken and white rice?
I'll continue to keep good thoughts that this can all be figured out soon.
Mom to Pixie - DOB 5/27/04
And rescue kitties Max and Sophie