I remember this book from when I was a kid, my dad first introduced it to me.
The book is set in late colonial period I think and is about a young impoverished boy and his family. The town in which he lives finds a wolf den, and he is the only one who can go down into the den. He agrees to go but for a price, he gets to keep one pup. The townspeople agree and when he goes down he finds five or six pups still alive. He picks one and comes out with it, telling everyone that it was the only one alive. He takes the wolf and begins to raise it. I know he watches an bald eagle kill a hawk, which he then takes to his professor/taxidermist friend and sells to him. That is about all I can remember.