Horses can't enter gates or 2 block spaces with trapdoors!

Horses cannot walk through spaces less than 2 blocks wide. They can't walk through gates (I figured that out after I made a complete 64 horse stable now I have to entirely redo it with the horses already inside) I have to push horses through two block spaces that have trapdoors on the sides to keep them from walking out even though the trapdoors are open! I want them to be able to walk through gates so I won't have to keep destroying the gate and the block next to it for it to walk out.