Thanks for replying. They are around 12 weeks old I believe, although the dominant male does appear slightly older. Their hutch is nowhere near that big (5ftx5ft) but they do have a run which I put them in every day to have a good run around. We’re contemplating re homing the dominant one as my Son has no interest in him and I don’t want them to start fighting. We can’t afford a bigger hutch just yet either.
They have plenty of hay so that’s fine and I have been giving them about that much veg each day too. What about grass/dandelion leaves? Do these have to be restricted or can they have as much as they like?
At their age they are not yet in their teens, so you do risk issues occurring within the next few weeks. While some people do get lucky with laid back boars who do want to be together and do make it together, you need to be prepared that the chances are not on your side. Most boar trios won’t get to adulthood with their bond intact. Issues likely to start occurring from 16 weeks of age. I’m so sorry you were sold a boar trio and told they weren’t likely to face issues - it’s frankly incorrect information.
You will always see dominance though, it is a normal part of how a piggy relationship functions. So even in a pair you will see it. It’s just that in a trio the issues are greater than dominance - its usually dysfunction and inability to form a hierarchy.
it’s also worth noting that it is normal for piggies to not sleep together, it doesn’t mean there are bond issues but again the fact you have a trio isn’t on your side.
If he becomes continuously isolated then that’s not necessarily a happy living situation even if fights don’t occur.
Is the hutch actually 5ft by 5ft or does that include the run space (and the actual hutch is 5x2ft)? A run doesn’t count as living space, only the enclosed part of the hutch counts and needs to meet size requirements. This is because a run cannot be used year round and piggies shouldn’t be in a run unsupervised or overnight.
A 5ft hutch is usually 5ft by 2ft and that means it is minimum size for two boars whereas two boars are recommended to be in a 6ft by 2ft hutch (not including run space).
There is no commercial hutch big enough for three boars together, and lack of space can exacerbate issues.
Should you decide to rehome one, rehoming the dominant might not be the right move. You need to keep the two piggies who get on best together.
If the one who is currently being left out and the youngest piggy arent compatible, then they won’t get on so by rehoming the dominant you might still run into problems.
You need one dominant and one submissive piggy in a pair.
The other thing is to split them up in a pair and a single. Then to speak to a rescue centre about trying to find a compatible friend for the one who is left single (it’s just whether you can manage with two pairs, and obviously you’d need two hutches of appropriate size and two runs)
Grass and dandelions are fine to be fed but needs to be introduced slowly if they are not used to eating them as too much fresh grass on unprepared tummies can cause digestive upsets.
Access to grass needs to be built up slowly each year after a winter off of the grass.
Feeding Grass And Preparing Your Piggies For Lawn Time
Do read the green links I’ve added in. They explain everything in more detail.
Some veg isn’t suitable to be fed daily (some is too high in calcium and risks causing bladder issues, some too high in sugar or too acidic in the case of carrots and tomatoes, some items risk bloat etc) so it’s a good idea to feed lettuce, coriander, bell pepper and cucumber daily. These are the safe main four daily veg. Anything else added in in rotation and moderation (with some things only suitable to be fed in small amounts once a week).
I have 3 boys of my own so my workload has increased somewhat since getting the piggies! Haha. 
