Hi and welcome!
How old are your boys? Boars go through a hormonal phase between 4-14 months old when they are more prone to fights and fall outs. You will also brace yourself for a renewal of the dominance in a new home = new territory.
Generally we recommend to give boars as much space as possible - for three boars that means 2x6 ft or more rather than the RSPCA minimum recommendation of 2x5 ft.
Guinea pigs cannot be fully litter trained; some are tidier than others. They are ground roaming animals and do not need to be as tidy as rodents that live in the same place for their whole life. Generally, they tend to have peeing corners, but you will find poos all over the place.
Please do not mix guinea pigs and rabbits. Guinea pigs need vitamin C in their diet, as they can't make it in their bodies, unlike rabbits; they have also other different dietary requirements.
You may find our boar guide with further links helpful:
http://www.theguineapigforum.co.uk/showthread.php?t=76162
More inspiration for housing solutions and a good diet you can get in the appropriate sections.
PS: We would be very grateful if you could add your rough location (country/state US or county UK). We are an international forum and the advice and links can differ quite a bit depending on where you are based. You can do this in User CP/edit profile/location.
