I am sure that this is one of those topics where I need to make it clear that this is my opinion only. I am not a vet by any means, and am only speaking from experience with my own animals.
I feed Purina Layena crumbles. I think when it comes to feed, you get what you pay for. If you invest in quality feed that uses quality ingredients, you will have quality eggs and healthy animals.
I have had to feed cheaper at times because of finances and saw HUGE differences in egg production, shell quality, and yolk color. I also saw a difference in my birds. And they were only on this "other" feed for 60 days. I switched them back immediately and have fed Purina ever since. I also feed my other animals that need feed Purina. They don't skimp on the quality of thier grains and use no bad fillers.
We also had our dog on Pedigree for many years and switched her to Eukanuba Large breed Sr a year ago and what a difference!
Again, you get what you pay for. They don't skimp on the quality of thier ingredients and it shows. My 9 yr old lab/golden mix acts 3 again. Her coat, teeth, eyes and attitude are so different now. It is amazing.
One thing about Eukanuba is you can call and they will send you coupons monthly and they are SO knowlegable.
Anyway, after owning animals all my life (And its been a long one! ha ha) You really do get what you pay for when it comes to what you feed your animals. Do reasearch as each animal is an individual and see what works best for you.
Good Luck!