Sorta off-topic...but having worked in a feed manufacturing facility for years, I can tell you this is false/misleading.
The texture of the feed and particle size are uncontrollable unless you "steam flake" all of the grains, which is cost prohibitive. "Small bits of junk/dust" are a normal part of the processing of any dry grain.
Processed feed is meant to be fed in a dry, stable environment...not dumped on the ground...pelleted feed is useless fed outside.
All feed produced in Canada is scrutinized by the CFIA, and subject to strict manufacturing/sampling protocols...and that includes deer feed.
Did I mention deer like apples.