I have and 18 mo. who is acting out in his class by hitting and pushing the kids smaller than him. He has 3 older brothers 4, 7, 14. Which says alot b/c he tries to keep up at home,but he is NOT bullied at home. and his teacher seems a little shaky about getting thru this. It has only happened 2x and he has been at this school since Sept. and only 5 kids in class w/ 2 teachers. I am confused b/c i think the teacher should be patient and firm and it seem like she feels he should be removed.
My first reaction is that he must be receiving this treatment himself somewhere. You may want to see what is happening there or any place else that he is left when you are not with him.
On the other hand he maybe frustrated. Often children who do not have a wide range of emotional vocabulary words are frustrated and act out. Try finding some books with feeling words in them and the faces to match and reading them to him. You can even play games with him with the books until he has more words to express himself. The teacher needs to encourage him to use his words as well. Hopefully she has been trained to reinforce his good behavior rather than give to much attention to negative behavior.
There is also a great little book about hands are not for hitting, feet are not for kicking, that sort of thing which is great for little ones who are acting out.
M Kay Keller