Within the room with the chair, there are three vents on the ceiling. The right-most vent is interactable and drops a pet. Upon interacting on the now open vent, you'll find a crawlspace that leads to the last pet.
Hope this helps.
i fed the um bunny on the thingy then crawled in it then fed the bunny the apple and then it says i have 2/3? idk what i did wrong
nvm\
