My daughter had the same problem. She went to a "special" public school that was as close to a private school as you could get. The majority of student were gifted & talented. You had to make application to go to this school. Since this was a very small school everyone knew everyone - parents included. I also volunteered about 3 or 4 days a week so knew the children's behavoior quite well.
When my daughter was put into a specific teachers class and I saw the list of other students I asked that she be transfered to a different teacher. All of the disruptive boys were in her class. I had seen firsthand how much time the Kindergarten and the 1st grade teachers had spent disciplining these boys(this was in 2nd grade)and I didn't want that much time taken out of the learning time of my daughter. The boys were good students but just being boys. I had a hard time proving that my request was only due to the boys and not the teacher. I didn't know anything about the teacher but knew that no one could keep a learning conducive atmosphere with them in the class. The group was not even split between the teachers but ALL of these boys were put into one class. (It's been so long I don't remember exactly how many there were but in remembering some of their names I come up with about 10 and the classes only had 18-20 total. So you can see that there would be a learning time issue.
I sat in on class for about a week and kept record of the times she spent having to deal with these boys. And the outcome. She was absolutely great however 75% of the day was not spent on education. I then did the same thing in the other teacher's class and the education time was over 95%!!
I submitted this to the principal and my daughter was moved the next morning. Also, both teachers met with the principal and the boys were split up equally. Just splitting the boys up made them settle down tremendously!! Both teachers were grateful for my observation!!! Best of all my daughter was happy there was no more "yelling"!!