Just leftover grain from brewing companies.
it was quite a normal procedure, and still is to feed live stock spent grains, lefrover mash of beets and sugar cane from the sugar industry, dried potato bits etc. It's very economical and still contains nutrients.
Egg production isn't usually affected by feed unless it's really low protein and old and in that case, it would likely stop.
We can't really answer this question unless you provide more information on what your birds get and do.
Treats/scraps? In a coop or free ranging?
What feed works best for...
What method are you using to decide what feed are good or bad for your birds?
Dumor is owned by Purina but they do their own milling. Both feed are fine.