K.B.
I don't know if he has the same foods at the daycare and at home. If the daycare is giving alot of juice/kool aid, the red dye #5 could be causing him to act out. It is not only in drinks but also in food. Also, watch his sugar intake, if my daughter (who is 3) gets too much sugar she becomes demon child. See if there is a certain time that his behavior gets worse (morning after drop off, after lunch, or pick up times)
morning drop off- he is missing you, doesn't want to stay, -drop in and see what is going on without the teachers knowing (I did this when my daughter started telling me teachers hit, the school denied it but it was happening)
after lunch- maybe really tired, or could be what he ate
pick up- again misses you, frustrated he isn't picked up
Try a behavior chart-- have 3 simple things listed ( ex. listens to teachers, shares, is kind) and have a spot for each hour he is there , if he is good that hour he gets a happy face if not he gets a sad face, If he can get 10 (whatever number you want) happy faces then he can get a special treat. Each week move the number up. If he gets 10 sad faces then he loses something he likes to do at home.
Hope this helps