I was hoping @casportpony would come in she would be the best for advising which antibiotic to give but here is her link to meds.
https://www.backyardchickens.com/t/...fungals-coccidiostats-and-wormers-preliminary
https://www.backyardchickens.com/t/...fungals-coccidiostats-and-wormers-preliminary