My two guinea pigs are only 11weeks old so they are still pretty small. There cage at the moment is plenty big enough as they are able to run around loads but as its a pet shop cage it wont be big enough when they are fully grown. So i was thinking in a few weeks/months i will build them a C&C cage but i want it to be big enough for 3 guinea pigs in case i give in and buy another one later one (not planning to atm though). So what grid size do you recommend and how do you make it a closed cage as i see most of them are open but i have a dog so it would need to be closed.