It's pretty much the same as any other conventional feed. The words you can't pronounce in the ingredient list are stabilized vitamins. Non-stabilized will quickly deteriorate.
All natural, has no meaning in the US. It's just a term they use to make it seem healthier.
Your chickens will do fine on it. However, it's not organic, soy free or GMO free.
You need to find a source of 50 # bags of organic but even those are pricey.
Perhaps you could talk your feed store into carrying it.