Hi There,
Well isn't this is an unusual situation
. I would suggest that you work individually with each puppy (to maintain control) and supervise contact via leash with one chicken and one puppy. Don't force interaction between the chicken and your pup, try to distract pup so the chickens become no big deal, but reward heavily when the puppy does not chase/assult chicken. Let the puppy get used to the chicken, and give treats (not chicken flavored lol) and praise for puppy ignoring or positively interacting. Gradually increase the amount of chickens present with the puppy(s), and continue to praise for positive interaction. Additionally, if you have a dog (you mentioned the Retriever) that interacts positively with your chickens, have her present while introducing the puppy to the chicken so that the pup sees how the other dog reacts to your chickens. Reward the Retriever in front of the pup for being mellow in the presence of the chickens. Good luck!