Somethings Wrong With My Poodle?

I have a silver St. Poodle and he sleeps in a huge cage in my bedroom right by my bed. I've been waking up in the middle of the night to find him like, gagging or making some deep, weird noise coming from the pit of his stomach and throwing up. It's kind of scaring me because hes only 1 year old and I don't know whats wrong with him. Before he throws up, when his noises start, he just sits there and gags. I feel bad for him. A few weeks earlier, I was giving him these raw hide bones and he started gagging and throwing up after I gave him those. I thought it was the little pieces he chews off. I stopped giving him those and got him some pig femur bone and he started up again. Ive not given him anything like that for a few weeks, and he still gags and throws up. Last night, I saw the throw up and there was some grass in it. But, in his other throw up, its just chunks. Hes fit and healthy, I would think. He gets proper exercise and food and water.. Can someone tell me whats wrong?