Just sharing an update here for anyone in this position. We had
Suprelorin injected into our crowing hen and… she stopped! Nothing else changed about her - tho she did molt slightly. She started crowing again about 5 months later. We decided to rehome her as, living in the city, it wasn’t going...
I'm thinking of doing this with my hen who, similarly is three years old, and started crowing, not laying, though her feathers haven't changed. Any update with your hen?