Did you mean a ton, literally, or just a lot?
Some great answers here and they point out a common maxim of feeding chickens: No one food should be the only food they receive.
For example, even with a balanced layer ration, some green feed should be included in their regimen for optimum health. This is even more so in the winter.
Read any feed recipe from the old days and wheat is a favored grain constituent, according to my research. But, but many other things contribute to the balance - the list of ingredients can be mind boggling, in fact. But, when you can get it cheap as you have, it can be taken advantage of without fear as a part of their diet, I should think.
If my advice mattered, it would be to continue giving them the scraps, allow the freeranging and keep the regular feed before them. All this leads me to wonder how they are doing currently, sans wheat?
A great, easily accessed resource for feed preparation iand knowldege is found in the old book by M.G. Kains, "Profitable Poultry Production." Just google that title and youll find it online for free.