@Truffolo
On a third thread I linked some information for you written by Wiebke with some info on baby castration and how it affects boar behaviour.
So, for my own experiences, I can't think off-hand that I ever got a baby boar from anywhere to be neutered. I think I got all my neutered babies from a rescue, when they were probably about 8 weeks old, maybe 10 weeks. They don't have a 6-week wait after early neutering. Afaik the operation is a lot simpler than for an adult boar, but I could be wrong. The babies are a lot smaller too, and that may affect their ability to get over it, idk.
Two baby boys, Snowy and Hughie, were born to my sow Poppet. But I kept them together and didn't get them neutered early, partly because I didn't know much about it at the time but mostly because after I got their father neutered, he died, I explained in post #24. I was devastated, he was such an adorable piggie by the name of Robbie (he had a little mask like a bank robber). I mentioned him in post #21 where I mistakenly called him Rubi (I've had so many piggies, it's hard to keep track sometimes).
I suppose the biggest difference I've come across is that in Germany the common knowledge among rescues and very experienced owners is that you can keep 3+ boars together. This must be due to them not going thru all those testosterone spikes the way Wiebke mentioned on the other thread I linked for you. The only time I actually had 3 boars together I mention in post #47 with pics in #49. I pet-sat them for about 10 weeks while their Human mum was in rehab. I think they had all been neutered but I can't remember exactly. I do remember that a bit later their Human added a fourth to the group who was too old to be neutered, he was probably about 6yo or so. The local rescue asked if she could try and add him to her group and obviously it worked. They were kept in C&C as you can see in the pics on post#49, so I presume she just expanded. C&C is becoming more common here but it's still not as usual as in the UK.
Another difference is that here it seems pretty uncommon to keep boars or any guineas side by side. The reason is maybe that it's easier to bond boys who were neutered early? You don't really hear or read about guineas being kept side by side. I've had fall-outs, like when a neutered boar, Snowy, died of old age one of his sows, Emily, went absolutely crazy and attacked any neutered boar or sow I tried her with, except her companion sow who she 'just' ignored. So I gave her to a rescue and they eventually managed to find a husboar she'd accept and they both ended up in the oldies group at the rescue. There are some pics of her and her story on post #37. Yeah so here if you have an irreparable fall-out and can't rebond your guinea with anypig, then you'd tend to go to a rescue with said guinea with the understanding that with all the guineas in the rescue, they're much more likely to find a compatible guinea for your 'difficult' one than you are, even if it takes a while. It's understood (here) to be better for guineas to be actually in a group than side by side and so for sake of Emily and her happiness, I gave her to the rescue. I realise it's seen differently on this forum and in the UK, and maybe in the US too. I'm not arguing about that either, just explaining because I think it might well have something to do with early neutering of boys.
Some very experienced piggy owners here even have whole herds of guineas, where they might have 2 neutered boars and a whole bunch of sows in one huge space. I suppose that only works with boars who were neutered early. Another thing some rescues here do is keep rescue guineas in at least groups if not herds. Just pairs is unusual. That way they can monitor who gets on with who, not just re particular guineas, but also temperament, e.g. whether a neutered boar definitely needs a wife or could be boar-compatible or possibly is best with a particular boar (happens occasionally). And then also whether sows seem best with a gentle, sweet neutered boar or better with a 'macho'. My Emily definitely needed a macho, after Snowy died. The other boars I had were both too sweet and gentle for her. Woolly moved in with old Suzie (Emily's previous companion) and it was love at first sniff. I can't remember if Emily attacked Woolly, but it's possible, (she attacked at least one boar). Certainly not compatible. I also had another neutered boar, might have been Rubi, who'd been Woolly's companion, but that was also no go for Emily. Far too gentle and sweet. He also went to a rescue, my local one, which was very small then, they had capacity for only 6 guineas, where he was adopted out very quickly to some happy sow. Of course I was sad to lose both him and Emily, but otoh I went from 5 guineas in 2 groups to 3 guineas in 1 group, much better for my shaky state of health and lack of energy. And I knew they were better provided for companion-wise then what I could do for them, at least in accordance with German views on the matter.
Since Snowy died and Emily and Rubi went to rescues, I've only ever had a neutered boar with 1-2 sows, usually 2. 1 only if it was a final pair before I stopped keeping guineas. A neutered boar with 2 sows is quite fun to watch, there's more going on than when you have only 2 guineas. For instance if one guinea wants to be left alone or is dozing, the other two will play or eat together, or just lie together.
There's also the rumour here that a neutered boar in with sows will help prevent them getting ovarial cysts, Wiebke has since debunked that! But I suppose the rumour is helpful for the adoption of boars from rescues! A neutered boar + 2 sows is a common threesome here, so there may be less need of boar pairs and herds, though not no need obviously.
Another thing rescues do here is put baby boars over 3 weeks/250g in with a neutered boar, especially one who's doing his 6-week post neutering wait, so that they learn guinea behaviour from an adult. Guinea kindergarten with 'uncle'. That way the rescue can also monitor future compatibility, roughly.
I hope I've managed to answer your question, tho I know rather imprecisely with detours...
Caveat: There may be rescues in Germany who do things differently, I have only had closer contact with two, tho what I've read here in G. on websites or books or spoken to other guinea owners about lends me to think these are German ways, experience, acquired knowledge.
