Been doing the same thing myself...tried several things and the thing that has worked best for me was a landscape (york) rake. Remove every other tine(big thank you to NonTypicalCPA) so the dirt flows through better. I set rake to kick trash out the right hand side. Up the field then back again to form a nice window of debris. Then I would straddle the window with tractor/fel and kids would through debris in bucket. A day or 2 of that and i went and bought a couple 10 tine pitchforks(silage fork). They pick up the bigger stuff, but the majority, they can just fork into the bucket easy peasy. One picks the big stuff, one or 2 will work silage forks. Worked all day doing this and snapped a few pics. Will try to post later.
I have tried several things, including a chisel plow with all the tines evenly spaced about 10" on the back row. Ended up having too much debris flow through. Tried chain drag...just gums up with debris quickly. Have covered many acres just picking by hand...slow and kids start hiding out from me on the weekends.
