Tom- where is this, in a general area? If it's southern Wisconsin, I'll bet they make it through the winter just fine, even though they are a late hatch. If it's northern Wi, well...not unless someone feeds them.
snow like that all winter last year? If the snow was like that all winter last year, in that area, then someone was feeding those birds, the hen and the toms she bred with, or they wouldn't be there at all this year, much less with poults.
I don't know of any one feeding the turkeys in the area. One neighbor leaves some corn standing which might have helped some if the birds were able to get to it.
usually the deer get it first Usually the deer get it first, and I'd be real surprised if a corn field could support a flock of turkeys for more than a month or so...much less almost four months of winter. I've never seen a corn field last that long, unless it's several hundred acres, and the deer population is very, very low. Now, if there's corn fields around there, I'd have to assume there's a farm somewhere, too, which probably means there's at least one silage pile...and maybe a couple of manure piles, too, particularly if there's cattle on that farm? That would get small flock through the winter.