When comparing prices, keep in mind that Nutrena bags are usually 40#, while Dumor and Purina bags are usually 50# - so what is cheaper per bag may not be cheaper per pound.
If Organic or "All Natural" hold no special value to you (they don't for me), my preference would be Purina, DuMor, Nutrena for their flock raiser/all flocks based solely on comparison of their guaranteed nutrition for a mixed age/gender flock. But I'm not certain I'd be willing to pay an almost 20% price premuim to get the Purina crumbles - nutritionally, its not 20% better. 10%? Yeah, probably - I'd paid that premium in the past, and would again.
That's a decision only you can make.