my local wild birds don't like milo, either - and even less, red millet!I used scratch grains as a treat for my chickens. I broadcast out a couple of handfuls on the ground, every few days for the entire flock. Mine were not particularly fond of the milo. Leaving it after they picked out the other grains. Which started to attract wild birds. So I switched over to straight cracked corn. Which they don’t leave a speck of behind.
Still, brings up a good point. Wild Birds are such common vectors for Avian diseases, you really don't want to be attracting them to the area of your chicken run, particularly if you are in an area currently experiencing an outbreak.
and if you free range, as I do, it is to some extent unavoidable - but efforts in mitigation (either ensuring your birds eat all the scratch, or ensuring the scratch is thrown far from the coop/main run, are worthy considerations.