Most if not all beasts are too big to fit in the doors. Possible solutions would be to make the doors 3x3 (or add 3x3 versions), or adjust the door hitbox to better fit the beasts.

The doors shall have a 3x3 large variant that will exist with the 2x2 normal. The foundation for the doors have been pushed in 1be789e, they just need to be modeled.