how much space should my zoo have

Question
I started out with 1 female, got another "female" and now I have 8 piggies.  The other "female" and his son are currently getting neutered (as I type).  The other 4 were born 2/14 and 1 has gone to his(her) new home.  I'm going to keep 1 of the new babies (along with the mother, father, and the original two babies born in Nov.).  So, I'll have a total of 5 lil' piggies.  I built my cage when I got my first one.  It is 5' long X 3' wide.  The sides are 4" high.  There's a "house" that is just a couple of boards screwed together that sits on the top of the one end of the cage.  It extends about 6" from the end and has a "mouse hole" cut in the middle so they can get in/out.  Will this be big enough for the 5 critters?  I do have a "lid" on it made out of 1/4" wire so they can't get out (and the cat can't get in).  I was thinking about building another one, putting it next to it and building a bridge.  But that means getting really detailed with the "lid" and I'm not a carpenter. Although, that would be the coolest cavy cage in the world!  My babies would be livin' large!

Answer
I have three piggies which stay in a 5 foot by 2 foot cage with a ramp that goes up to a 3 ft by 1 foot 2nd floor.
Your size is suitable for 5 piggies but if you plan to rebuild a cage, I would make it a little bigger. It is recomended that you have at least 2 square foot for each piggy, which for 5 piggies is 10 square foot, and you have 15, so you are good. Thanks!