I have a puppy approximately 14 weeks old. He is resistant to walking. He doesn't seem to have any particular fears to anything, however he grabs the lead in his mouth, refuses to walk, won't leave the yard, etc. When I try to get him to go he becomes somewhat aggressive and tries to bite my feet, legs and hands. I have never heard of a dog, especially a puppy that is so resistant to walking. Any suggestions?

Occasionally some are like that. I have managed with younger ones just getting out at the end of the leash and coaxing it. You could also try running in baby steps.

Last of all, only away from traffic, drop the leash and walk off. Perhaps try playing with a ball.