Dr. Anukarna Singh
If they have been checked in detail(preferably with some blood tests) and the doctor is certain that they are healthy, you can try flavouring their food by adding a few drops of coconut oil, olive oil or butter in small amounts to improve palatability. You can also try cooking their food in a different way,eg bake instead of pressure cooking. You can add a few leaves of coriander or mint and also a few herbs like a pinch of coriander powder/origano to improve the taste. You should also work on training them