Agreed, my apologies.Age is largely irrelevant when it comes to bonding piggies. It is character compatibility which is the key to whether a bond will be successful.
However, given your piggy is in his teens, then bonding him during this time particularly with another boar is harder.
If you were to get a younger piggy then as that younger one enters his teens, your current piggy will still be in his teens and this may well cause problems.
Often in this situation, the safest thing is to have him neutered, have his six week wait for him to come infertile and then bond with a sow. A boar/sow pairing is often the most stable of bonds.
The safest way to go about bonding is via a rescue centre. They will be able to ensure a piggy of suitable character is found - they may be able to bond him with a boar, but as I say, for a teenager, it can be harder - and that way you know you won’t have problems. If you go out and buy a piggy on spec, particularly to bond with a teen boar, then you will be taking the risk of failure and therefore could end up with two piggies who can’t get on and must live separately.
Contrary to the advice above, bonding with a 4-5 month old would be largely problematic given a piggy of that age is just entering his teens so would be starting to experience some of the highest levels of hormone output
Nobody knows I'm afraid as it's all down to mutual liking and character compatability. If they don't get along you could always split the cage (if it's big enough) and have them as live alongside companions.question i found a 3 year old guinea pig would that be good?