I just lost a hen to egg yolk peritonitus. I read that people had great success with Duramycin-10. However it seems impossible to find. No one has it in stock in stores or on line. Also I was told you need a script from your vet. I finally found a local store with Terra-Vet 10 Tetra cyclilne Hydrochloride Soluble Solution which has exact same thing (25g of tetrahydrochloride activity/pound) as Duramycin...same exact language on the package, no script required. I'm starting my other hen on it as a precaution because she's been pooping yellowing loose stools after a solid one. Has anyone had any experience with this Terra-Vet 10 ? Anyway if you've been looking for Duramycin-10 maybe this will help some folks.