With fewer birds, I'd just get one bag each at a time. The grain will last, dry, in a sealed can for at least a month and a half, if not more. I get feed every 6 weeks, and the last can's worth still looks just fine.
So, my feed stores prices: Catfish pellets $25.50 a bag. Oats: $12.95. Barley $14.95. BOSS $25.50. Scratch grains $12.50. So, one set will cost me $91.40, but you'd only be using about half of the catfish pellets with that batch. They're a dry pellet like dog food, so they'll last a good long time.
So, my feed stores prices: Catfish pellets $25.50 a bag. Oats: $12.95. Barley $14.95. BOSS $25.50. Scratch grains $12.50. So, one set will cost me $91.40, but you'd only be using about half of the catfish pellets with that batch. They're a dry pellet like dog food, so they'll last a good long time.