Dog does not eat by his own?

I have a male Cocker spaniel, he is 1.4 years old. For first 6-8 month I feed him with my hands as everybody does. Then I started with keep food in bowl. He was eating from bowl but now he hasn't been eating properly for the past few weeks, he refuses to eat his normal food (pedigree) so we've been cooking eggs\cheese etc. Then after a while he doesn't eat himself unless we feed him by hands.  He doesn't seem to have the energy when he doesn’t have food. I'm really worried and I don't know what to do. Please help me figure out what could be the problem and why he is not eating by his own. Is he bored of food? Thank you so much for your time