Oh Jings pink
where did you get them (I'm guessing a private seller rather than a Rescue or a Petshop (given their age- Petshops usually turn them out younger)
Who told you to get them neutered, the owner?
And why were they selling/re-homing?
You've got them now, so buckle yourself in 
First off - boars are lovely (my DD wanted boars, we had a few years with boars now we have sows. The sows are gorgeous but boars have character like no other)
They also go through The Terrible Teens (aka The Kevin Years) at about 4-6 months which may well explain the reason why they were rehomed.
And trios of boars are hard work. A duo will live nicely with enough space and distractions. Trios of boys can be done but it's harder.
Don't neuter them unless you want to pair them with females. It doesn't change the fighting tendancies.
The one with the damaged eye? How long ago was this? Has he been looked at by a vet? Treated?
If they keep fighting you will need to re-assess the trio which may well mean taking out the one who is being picked on for his own safety.
Usually with a boar pair there's a dominant boy and a quieter one. If they maintain their Status Quo (not the Pop Group) they will jog along happily. One protects, the other is the protected. There might be the odd fracas (mine certainly did) but it's resolvable in most cases.
You can't put a boar pair in range of a sow but you could have a boar+boar and a neutered boar+sow if they are kept well apart.
A hutch for three guineas would need to be at least 5'x2' but for boars increase that - as much space as you can.
Your hutch has upper/lower levels . You'll find they'll spend most of the time in the sleeping bit for now, the grass might be too damp at the moment.
If you can, get a big rabbit run that folds up for storage. Peg it down with tent pegs to protect them. Lots of tunnels and boxes.
You've jumped in the deep end there pink but we're here to answer all your queries