Guinea pigs are unable to be housed individually, they are very sociable creatures and seek the company of another guinea pig. It is recommended that they are housed in same sex groups. This is due to potential aggression from same sex pairs, towards one another. To reduce any chances of any potential aggression, it’s smarter to house pigs of the same sex them separately, unless they are together for breeding purposes. With male guinea pigs they should be housed in smaller groups, this is because they have short tempers ( around sharing of food and water etc ). Female guinea pigs are able to be housed in larger groups as they are less aggressive and don’t show as much dominance as males. However introduce them slowly and in a controlled way.
Guinea pigs should be provided with ample hiding space. If you are housing 3 guinea pigs, there should be at least 2 hides, these should be large enough for the guinea pigs to all hide in together. The more hides available the less aggression they will show. A guinea pig might become aggressive when scared. Guinea pigs should ideally be housed in a large floor pen with plenty of space to freely roam. Younger guinea pigs have much more energy than fully grown adult guinea pigs, this should be accounted for in the housing set up. The guinea pigs might attempt to climb up the walls. When fully grown the guinea pigs should be able to stand up onto their back legs with ample head space. Try to avoid opaque surroundings, as guinea pigs will find this stressful to not see who is approaching them. If you would like to buy a ready made cage for the guinea pigs, you should buy the largest cage available to you. The more guinea pigs you are housing the bigger the cage will need to be, if you are housing 2 guinea pigs together : 7.5 square feet (minimum), but 10.5 square feet is preferred; generally 30″ x 50”. If you are housing 3 guinea pigs : 10.5 square feet (minimum), but 13 square feet is preferred; generally 30″ x 62”. If you are housing 4 guinea pigs : 13 square feet (minimum), but more is better; generally 30″ x 76”.
Guinea pigs should have a thick layer of base material to walk on, grid floors are not recommended due to the potential development of pressure sores and foot infections ( pododermatitis ; bumble foot ). The best flooring is dust free wood shavings with sufficient hay on top and in the guinea pigs tubes. Guinea pig teeth grow very quickly, and continually throughout their life, needing to be closely monitored, such as you would for a dog / cats nails. Make sure you have some wooden blocks or chews so the guinea pigs can wear their teeth down, this will reduce to possibility for veterinary dental care. Pelleted diets can increase the risk of dental work, therefore providing ample hay will help them naturally grind their teeth down. You can provide your guinea pigs with some tubes for them to hide in, these can be PVC tubes, cardboard tubes or even hollow wood tubes. Make the tubes long enough for one guinea pig to fit in, if 3 guinea pigs where in one tube they would become stressed and feel trapped.