If they are really all cockerels, then I would feed a flock raiser type feed rather than a layer feed. Cockerels don't need the extra calcium in layer feed. Brand is less important, protein content usually 18 -20 percent. Purina Flock raiser, pictured in the above post with pictures, is usually easy to find and widely carried. If you can't find that then you can use a start and grow or grower feed, those also do not contain the extra calcium. I use them when the flock raiser is not in stock. Just get them on a good, balanced feed and stop the corn and sunflower seeds except as very occasional treats in small amounts.