Hi, We are working on a similar problem and have come up with a few fixes (but it is still a work in progress):
We have a siblings table with coloring books, paper, crayons. A sister who need communtiy service hours mans the table (but is not an official babysitter).
We have a parent breakout to run business past the parents and limit the chatter in the main area.
Station activities work well. The boys keep switching activites and this keeps the interest level high. You can always get more parents to help if the boys keep moving around.
I don't know how teachers do it. Keeping control of a bunch of boys is a tough task.
Good luck.