I've raised and trained 3 Golden Retrievers to be my silkies companions and protectors. The younger the dog, the easier to train.
Start by exposing the puppy on a leash for several days. Call the chickens over. Each time the puppy takes interest in the chickens, gently yank the leash downward and saying a firm "NO". Keep watching the puppy's reaction and consistently redirect his attention by leash yank/NO.
Walk the puppy around the chickens on a slack leash. If he starts running after them, gently roll him onto the ground on his side and place your open hand across the side of his face. Firmly say "NO". Let him get back up and start over. Never let puppy out of your sight after removing the leash. It took 3 weeks to fully train each puppy.
Another tip....you may want to start the exposure with a rooster, will leaving the slower hens inside a pen.