At what age, do you recommend that I begin feeding my puppy bully sticks?

You don't really "feed" bully sticks; they are an appropriate item for chewing. I use them from the moment I bring my puppy home. They are life savers! I would caution you to keep a close eye on the puppy when chewing them as he or she gets older. I find that usually once they get through the teething process many aggressive chewers (most of my Mals) can no longer have these because they will eat the entire thing in one sitting and get it down to a dangerously small piece that they may swallow whole. I use the super monster size for my Malinois and German Shepherd puppies.