Again build this up gradually. The younger you can introduce your puppy to the chickens, the easier it will be. Give them a gradual exposure both from outside the enclosure and then inside the enclosure under supervision. Chickens will generally tell the puppy of for getting too close by pecking them.
If your puppy is a little older and they are quite keen on chasing the chickens, put a long line on the puppy. Reward them any time they are not running towards them and if they do make an attempt to chase. Give the line a gentle tug to get your puppy’s attention back to you, call them to you and reward them when they are back with you and calm. Build up exposure gradually to suit the pace of your dog.
Rabbits and Other Small Pets
Just build exposure up in a supervised and gradual way. Get them used to being around each other. When in the pen with the rabbits, always make sure the rabbits have got somewhere to hide as they are more easily startled and intimidated. A pen with the rabbits in is a really good controlled way to let them get used to being around each other.
Remember with any animals, you want to reward your puppy with lots of verbal praise and high value treats whenever they are around the new animal but remain calm and relaxed.