Did you just blow your cover? Different username from OP so how do you know if he pays bills and where they are--or are you the boyfriend.

Assuming you're OP, then NTA--Boyfriend shouldn't be dictating and imposing rules in your house that significantly impact your quality of life. If he can't put his chickens in a large coop so they have a safe place to be without negatively impacting your dog, he needs to either move and take his chickens with him. Even if he was paying for half of the rent at your place, he STILL needs to be more considerate of the impact that his dream of having chickens has on your (and your dog's) day-to-day reality.

If he can't see this, he isn't a good boyfriend and I wouldn't count on him being a good husband. Narcissism is real.