I think they're part of the vitamin/mineral pellets(along with the black and relatively small ones in the mix but in this case most likely more grain based than alfalfa or grass hay based).
You could definitely try using those as part of a hand feeding session(or just hand feed them throughout the day,whatever works best!)instead of adding more treats.Practically all of Higgins Sunburst would be easy enough to hand feed though,with the smaller millet type seeds in the mix being the only potentially difficult parts to hand feed
