It's actually not too uncommon for them to have diarrhea this time of year, especially if they free range. Think about all the weird stuff they're eating...plus if it's hot, that can cause diarrhea too. I just gave our flock some fermented feed for a week...I give it once a day, every other...
I never treat for both at the same time, just because I think it's a little hard on them....but you can. Just make sure to continue to give them the vit/ lytes and probiotics for a bit afterward, and the ZyfendA. Good luck, hope it helps!
Usually older birds don't get Coccidiosis but they...
If you have a regular vet for your four leg pets, the vet should do a fecal exam for you. If they say they don't do chickens, just tell them the poop and parasites are basically the same as any other animal. It might be coccidiosis. It's worth having a fecal done just to rule parasites out...