Right, way too much scratch. I'd cut it out entirely for a while, or at least reduce it to about 1/4 cup for the bunch. I'm not sure about the alfalfa/hay mixture but suspect it is also pretty low in protein. BOSS is a good protein source but it seems like that's a lot for a few chickens. Maybe just give them feed and a treat of sunflower.
I've never had mine refuse to eat pellets, or even hesitate to, but I have large fowl; maybe for bantams they were just too much to manage. Also, mine are accustomed to my offering very little besides pellets. Treats are not a daily thing so whatever else they get, they find foraging. Usually people on here say just leave them with the pellets and they will eat when they get hungry. Again, the extras may discourage them from learning to eat the pellets.