how to keep the food in the feeder?

My 5 week old Marans and Orps are hungry messy pigs. I've been using a brooder with newspapers for the bottom, and they would tip their food over in their feeding frenzy, and then just eat it off the floor. I just moved them to a wire floor brooder outside and got them one of those mason jar chick feeders. I filled it up, and came back an hour later to almost all of it spilled onto the tray under their wire. weiners. Is there a better kind of feeder to keep the food in? I have it barely filled now, so they really have to stick their head in to eat. I think that has slowed them down a little- or else they just cant reach it either to eat or make a mess