Instructions
Quarantine your new pigs for two or three weeks before putting them with others. This allows time for any illnesses they may have contracted to show up. During the quarantine period keep the new pigs in a separate room and wash your hands after handling them and before touching your other pigs.
Bath all the guinea pigs in a safe shampoo before introducing them. A lavender shampoo, or similar, will cover their scents for the initial period, making the introductions easier.
Wash the cage and accessories, change the bedding and rearrange the inside of the cage to create a fresh, new, environment for the pigs. This will lessen any potential territorial issues. Also provide them with separate sleeping quarters in the cage so that they don't fight over a single area. Put a dab of vapor rub, or lavender oil, on the tips of the pigs noses to further disguise scents for the initial meeting.
Introduce your guinea pigs in a neutral environment and give them vegetable treats and toys to play with. This should help distract them as they get to know each other as well as making it a positive experience.
Observe how your pigs are getting along and be ready, with towels, to intervene if a physical fight breaks out. Guinea pigs make screaming noises sometimes during play, however, so don't jump in unnecessarily. Just be vigilant.
Move your pigs back to the redecorated, renovated cage if they seemed to be getting a long.
How to Introduce a Baby Guinea Pig to an Adult
Having fallen in love with your first guinea pig, you may feel that you want to have more. Guinea pigs are naturally social animals and are happier with company, so having at least two guinea pigs makes sense. As in the wild, however, some guinea pigs, particularly males, or boars, have dominant tendencies that can make introductions tricky. Luckily, when introducing either baby boars or sows to an adult you already own, the adults, of either sex, often feel protective towards the little one, rather than threatened by it, as they might with another adult. While introducing baby pigs to adults is easier than introducing two adults, there are still some steps you can take to ensure a stress-free transition.