My youngsters do that too. I had a bunch in a temporary pen once, and the bottom wasn't quite flush with the ground, and a bunch got out. When I came out with the food, a bunch of them started running across the yard towards me. This usually happens when they run out of food. Make sure they always have food available.
If they are seriously crowding the door, I throw some feed towards the back of their pen, and they all run there. Unfortunately, this only works if you keep them on the ground or on a solid bottom cage.