Why indoor pigs need the bigger number
Outdoor and part-time guinea pigs often get grazing runs that quietly subsidise a modest hutch. A pair living indoors all year has no such subsidy: every lap, every popcorn and every retreat from a cage-mate happens inside the enclosure, so 10.5 square feet for two pigs is the genuine starting point, not the generous one. The familiar grid pen of 2 by 4 panels lands right at that size, and stepping up to 2 by 5 gives sows room to pass without negotiation and boars room to keep a civil distance. Single-level still rules — indoor ramps add cleaning grief and no usable territory.
Building the pen for life inside a home
Indoor housing succeeds or fails on its base. Put a waterproof layer — a cut-to-size correx sheet, a tarp under fleece, or a large washable mat — beneath everything, because hay dust, water drips and the occasional missed corner will otherwise reach your floorboards. Site the pen where the household actually lives but out of direct sun and away from radiators; guinea pigs overheat easily and feel safest with household sounds around them rather than in a silent spare room. Raise the pen slightly on a low stand or table if bending to floor level makes daily care a chore nobody volunteers for.
Layout for pigs who never go outside
Because the pen is their whole world, furnish it like one: two hidey houses with two doors each, a hay tray or hay pile big enough for both pigs to bury into at once — hay is bedding, food and entertainment for indoor pigs — a tunnel run along one side, and a covered fleece corner that reads as deep shelter. A small kitchen area at one end, where pellets and water live on an easy-wipe mat, keeps the rest of the fleece drier and stretches the time between full changes. Rotate toys and rearrange the furniture weekly; novelty is the indoor pig's substitute for new pasture.
The indoor-only health watch
Life indoors removes some risks and adds others. Without grass, the diet leans harder on hay quality and a daily vitamin C source from vegetables or pellets made for guinea pigs, since they cannot manufacture their own. Nails grow without outdoor wear, so fortnightly checks belong in the routine. Watch weight and energy: indoor pigs in an undersized pen move less and graze from boredom, and the fix is almost always more floor and more furniture, not less food. Lively laps at floor-time hours and two pigs sprawled in separate favourite spots tell you the size is right.
An indoor herd lives in the middle of family life, so KinsLe Family Sharing puts the pen layout, the veg list and each pig's weight notes on one shared profile the whole household works from, whoever does the evening feed.