Is your vet using deslorelin implants? We have had huge success with them. My hen at almost 3 started having trouble laying, ended up with egg yolk peritonitis in which she developed a heart murmur from! We treated with Clavamox for 30 days, deslorelin implant and now she is all better. The implant can last 6 months - 1 year. For my girl it lasted 8 months and then she needed another. Highly recommend for those people who do not want to cull/euthanize their hens with reproductive issues !