I won't try to compare my flock with breeding silkies, but you'll have a hard time convincing me that Kamblach (or insert other) is that much better than Purina flock raiser at $16.99 locally or even at $20.99 on the TCS website. Yes, I do have to add oyster shell, but my environment is calcium rich....I can't calculate it. Maybe $6.99 a year?