I didn't start giving Traveler any scraps until he was 5 years old-maybe 6. He's been on Orijen regional red and/or Orijen 5 fish. Both are grain free. For treats he gets a raw frozen marrow soup bone. I don't think boiled chicken is going to put any weight on your pup if that's why you are asking. If it's just to ask about feeding something different, then I'd start with a little and keep your eye out for any negative reactions. Traveler happens to get allergic response to turkey and chicken and recently I had him tested for food sensitivities and whitefish and salmon came up really high
Wish I could offer more help but I'm not as experienced as lots of other members here.