Hi there,
I had a hen put on Suprelorin after extensive treatment for EYP (abdominal draining, IV fluids, abdominal lavage, antibiotics, anti-inflammatories). It is a small capsule injected whole with a very thick needle. Our main avian vet put it right into her breast muscle, but a different avian vet told me he prefers a subcutaneous injection on her upper back so it stays in the system longer. If you pursue this route, I suggest you discuss with the vet where on the chicken’s body they prefer to inject and to explain the pros and cons to you. They may have a practice of just one site or another, but it would be nice to understand the rationale. The implant was very effective, yet only lasted about four months. She died just a few days after her second implant, but she was starting to show signs of salpingitis and never fully gained all her strength back after EYP (which progressed very rapidly). The implants are expensive, but for me it was well worth it to have a few more months with her. It would have been an ongoing problem without the suprelorin and would have killed her much faster. She did have some good quality of life for awhile there.
On a side note... when summer heat hits, if your hen is still with us, do NOT put her in water to cool her off. That’s how I unintentionally killed my sick girl. Everyone else perked up after their dip, but I did not know at the time wetting a sick bird can push them over the edge. Devastating. I hope people learn from my mistake. Makes me misty eyed still to this day.