They are such pigs.
I would probably feed 3 at a time, at most.
I feed mine 2-3 in the morning, 2-3 at night, and a few times a week they get a wormy with their meal. I could probably get away with feeding more, but in smaller amounts multiple times a day, because they are quite active, since they can see eachother and whatnot.
It seems that too many pellets at once could have some repercussions, but I am not sure.