Normally by springtime most crops have long been eaten up. However , with all the snow this year it is possible that some food is still around. Whether turkeys would still eat it , I don't know.
The turkeys will be around open ground to strut and find hens , but don't count out them feeding in the cottonwoods. They will already likely roost there and there are usually a good crop of snails under these trees. I grew up hunting the Mississippi River bottoms and when mast crops were slim , the turkeys would be found feeding in the cottonwoods.