That's a very good point from deep in the woods of the South.
We should all keep in mind, they are just like every thing else, none are equal. They all live differently from day to day.
I have Never seen any info on the question asked, but did read that a turkeys weight was at it highest during February. This made sense to me, for My area. Some places up north I think would be early than this as the set in of winter occured in November and December.
Also depends on how many corn and grain piles might be laying around. Seriously.