I would suggest pre-treating for chytrid, the disease is very widespread through southeast asia and Megophrys are often "silent carriers" until stress weakens them enough to show symptoms. I have had great results from Steve Busch's Lamisil treatment.. If Lamisil is not available where you live you may have to look into other treatment methods.

For feeding I just drop the insects in and let the frogs catch them, they are fairly timid frogs and will actually shy away from attempts to hand or tong feed them.