You are doing well with 200 lbs of feed per month. An adult chicken eats approx 1/4 lb per day. So 65 chickens would exceed 400lbs a month, so you don’t have much waste, and they are successfully foraging.
fermenting feed, or even just mixing with water, is a good step, so that has been good for the budget.
some people plant good forage for the chickens in the field or garden, but no idea where you are located, nor if you have space for that.
some people grow fodder indoors for fresh greens for the chickens.
some people will feed cheap corn and/or leftovers. However, the health can suffer or egg laying if things get too unbalanced.
some people supplement with dry cat food - as it can be around 30% protein. However, you should never make this a significant part of the diet.