[RESOLVED] Barnyard door...or something... [RPGMAKERXP]

I have these animals in a pin on a map, I want the player to be able to get inside of the pins, yet prevent the animals from getting out, yes the pins are shut.
What's the correct way to event a gate like part that can let the player in, and out?
Sorry, mind's a bit fogged, and I can't think properly.

Do you mean PEN?
1.You can make the animals move according to what you want by editing the Move Events in each Event.
2.Make an event in the pen entrance that pushes the animals back when they approach it (If they move randomly)