I always wonder about nose bags .
Once it is on , a horse has to breath in the bag , and that would mean any dust , bits of chaff etc , are going to end up in the horses lungs !
I know mine blow rolled oats or barley all over the place when eating and i assume a bit goes up their nose . But eating from a bucket , they can just lift their head up and out of the bucket .
Maybe i am just being too fussy ? Could never test it with mine though , they would go ballistic if i stuck a bag on their noses ! lol , so i just do as you do Karen , and stand between them , only got two now , so it is a bit easier .
Maybe mix extra chaff with the oats ( or whatever feed they are on ) , in greedy guts's bucket , so donkey no nuts , can get through his faster ?