L.R.
Was this just at this one meeting? Are all meetings or most meetings this chaotic? If they were crazy at the start and end, blowing off steam, I could see that, but if they were nutty every five minutes you say, and if most meetings are this way, it's past time for other parents to offer the leaders some help here, I think. Are these leaders going to welcome that or be all huffy and offended? If the latter - I'd look for a new den, maybe.
Do the leaders have specific activities planned for each meeting? Are the activities age-appropriate (as in not too "old" or "young" for these kids but things that are achievable and engaging)? Do the leaders have ALL the needed supplies there and set up ready to go before the kids get there and go nuts? Does the meeting have any kind of official opening 'ceremony" or activity that signals to the boys, every time, consistently, that the meeting is starting right now and now is the time we drop the pre-meeting running around? Does the meeting have a clearly defined ending, another ceremony or consistent ending activity that, again, signals to the kids that now it's time they go? In short -- is there structure, and are activities good, realistic, organized and engaging? Do the leaders run out of activities and often end up with time where the kids are not doing something specific so it turns into a melee?
I totally agree with the post below saying the den needs one active, high-energy activity at the start to get the boys to burn off some energy. But the leaders MUST be able to bring the boys back, after an active time, to whatever else they're trying to do during that meeting.
I'm asking all this as a Girl Scout leader but I think the ideas apply to any group of kids, including our Cub and Boy Scout brothers.
One other thing parents of these boys need to consider -- if this den is ever going to do a field trip (fire station, police station, local park to cook out, whatever) or especially if they ever are going to go camping, you truly need a lot more adults present. I would not attempt any form of outing until the boys and leaders have had a string of successfully organized, calmer meetings that show the boys will listen to these leaders.