Yep, Ed had it right, the bear bags are feed bags that weigh a couple ounces each (they really aren't that weighty) and are approx 18" wide x 3-3.5ft tall. About 4-5 per crew (depends on size of crew though), but if you brought 6 of your own you would have plenty.
I agree, spliting food into tent pairs works well, but work with the kids on going through each bag and taking out what they don't want or trading with others in the crew. Then have them raid the "swap boxes" to find other things they want. This will result in less waste, bulk, and more happiness.