I get around the billing problem by having feed as large particulates where possible. This means intact grains which not a problem so long as grit levels are adequate. My adult birds can ingest whole acorns and three week old chicks can ingest whole corm kernels. During summer month...
Fermented feed can taste better. The fermentation process can break down some complex carbohydrates into simpler sugars and alcohols thus impacting taste. Some anti-nutritional factors may be broken down. Some of the additional byproducts can serve as vitamins. A down side nutritionally is...
Even 13 acres will be tight without supplementation. Without supplemental feed of some sort they will range farther afield to meet their needs. If they go too far flock bust up to occupy roosts closer to quality feeding areas and / or become more vulnerable to predators. I suggest putting out...