my bp isn't interested in live food anymore????

[PO_0784]

Ok, my ball was first introduced to live mice..he was on dead mice for the last half year (he is about 1 yrs old). Now I switched to rat because he was eating a bunch of mice in one shot (4) lol..he did take his first rat (a dead one).. but then I tried again last week and he didnt seem interested. I tried live rats at least 6 times since then. It has been since 3 weeks he didn't eat. When he see the rat(a live one) he follow it like a mouse but when he get close, he seems to dislike it or I dont know(maybe he doesn't recognize that as food???). Help me! Im really worried about it!
any tricks to get him on rats?