This tip isn't mine, but it's buried, so reposting for anyone going for the badge - vote up if it helps! From level 8 on, just grab a vehicle and hold it just below and to the left of your nest; it will block any shots at the babies. Wait until you have a crowd right under the nest and drop the vehicle; you'll get quite a few bodies in the next, and the combos will fill the hunger meter in no time. Turns the badge from impossible to nearly effortless. This worked for me on the first try, after at least a dozen other tries for the badge.
I'm thinking the computer needs to cheat a little less obviously. Getting multiple beholder cards into play in the first 2 minutes of a battle, when there's no way for it to have enough souls for one?
 "Nuclear Eagle"){kind=icon}
 "Cardian"){kind=icon}