Hi and welcome to the forum!
Could you please tell us where you are located? You can add your country/rough area to your details in User CP/edit profile/location; that makes it much easier for us to pitch you appropriate advice and links, as we have members from all over the world.
Here in Britain you have the option of "boar dating" lonely boars of any age at a good rescue where they are introduced to suitable candidates in order to find a character compatible mate (the key for every successful boar bond) under expert supervision. That is not something pet shops or most breeders can do or are interested in as it is time consuming and not money making; hence the myth that adult boars can't be bonded! mallethead
There are actually two forms of dating available, depending on the rescue:
- full residential boar dating where any promising boar bond is stress tested for a few days before the boys are allowed home - this means that any resulting successful bond is as stable as a sow bond and that boars of all ages can be bonded with each other.
Here is Suzy's boar dating blog from her rescue which she kindly keeps updated for us. So far all bonded boars from that thread are still together. So much for the myth...
http://www.theguineapigforum.co.uk/showthread.php?t=59233
- speed dating with a baby/pre-hormonal boar; most boars will accept a congenial youngster but there can be problems when the younger boar hits the big hormones later on. Generally a bigger age difference is of an advantage in this kind of bonding as it keeps the dominance clear.
Things get a bit more tricky for those who haven't got access to a rescue. In these cases getting a baby is the best option, preferably from a place that allows your boy to meet some and make his choice who he likes best. The risk of the bond not working out is correspondingly higher. We have bonding tips available if you wish.
Here is a map of (vetted) recommended rescues in the UK; most of which offer boar dating on one form or other:
http://goo.gl/maps/mKDT