feisty ferret cage

I just got a feisty ferret cage for my chins. I'm going to have to modify it somewhat but my question is... do you think it's big enough for 4 chins? 2 on top and 2 on the bottom? The cage dimensions are 31-inch long 20-inch wide 41-1/2-inch high ( 54-inch high on stand) with 7/8-inch wire spacing.