It might depend on what kind of feeder you have. If it's like mine, a metal bucket that has a space at the bottom that gravity feeds into a bottom tray (does that make sense)
I had to raise it up onto a cinder block. When it sat on the floor the hens would sort of scoop it out onto the floor, but when I raised it up they couldn't get the right angle to scoop it out. I also put a 2x4 on the floor as a barrier between the food area and the general coop area to keep any food that did get spilled from being kicked out onto the main floor area. Some pine bedding does make it over the 2x4 but the seeds and pellets stay in the food zone.
I hope I've explained it okay.