Hi! Please take the time to read these very detailed and informative guides. They should hopefully answer all your questions. Your boy may need to wait until his testicles have descended; then you are looking at another 6 weeks post-op safety wait before he is 100% safe to go with sows. sepa
Neutered / De-sexed Boars And Neutering Operations: Myths And Facts
Tips For Post-operative Care
Please be aware that boars start making babies from 3-5 weeks and that sows have their first season from 4-6 weeks onwards. If the sow and boar pair you want to acquire are living together, it is most likely that you are dealing with a pregnancy. In this case, please open an ongoing support thread in our pregnancy section and read the relevant guides at the top of the section; they cover the whole period from pregnancy through birth to baby care, sexing and separating baby boars.
Please always double-check the gender of any new arrivals or your own piggies if you have never done so before before you introduce any newbies. Mis-sexing is surprisingly common, as is ignorance about when guinea pigs become sexually mature!
Sexing Guide