Need advice - Where should I put food

Hi
I've been missing the forum for quite a while as I've been very ill but my 4 silkies and my schnauzer have kept me going. It's nice to be back reading all the threads. I would like some advice please. I built a big run around my chicken coop about 12 months ago (sawed all the hard wood by hand - not a good idea) and have put pavers down in over half the run and placed the coop on the pavers. My logic behind this was it would be easy to hose the pavers to keep the run clean and I do this every week. I have put an awning out the front of the coop to cover an area where I put the chikens food and water as I haven't been able to put a roof on the run I built as yet. My question is this: I have their food in a large dog bowl (one of my chickens is one I adopted because it has a crossed beak and it is easier for her to get her whole head in to get the food) and the bowl is on the pavers. Given it is chickens natural behaviour to scratch, should I put the bowl on the dirt instead of the pavers so they can scratch and get the bits that they flick out of the bowl. I'm also looking to waste a bit less as I hose or sweep the dropped food and poop off the pavers at least once a week. Your advice on whether to pull up some pavers and put the food bowl on the dirt would be appreciated. Thanks so much. Justine