It depends a lot on where in Iowa you're gonna be (north vs south), how exposed to the wind you'll be, and what the actual temps turn out to be.

The weather here can be extremely variable. Last year during shotgun season (2nd week of december) it was 52 degrees. The year before the same week it was 12.

I don't know as far as specific recommendations, but I usually do a base layer of under armour, then long sleeve t-shirt and layer on top of that as needed based on the forecast low. That way you can always remove layers. I'd much rather have too much clothes on and drop a few layers than freeze my @$$ off.

That said, Cabela's has a nice line of Mossy Oak camo that has a pretty decent pattern with good scent control and arguably more importantly; good insulation at a decent price.

I'm not made of money, so I usually find the name brand stuff I like then look for the Cabela's brand equivalent which is usually 25% cheaper or better.

Good luck!