They might well have been glad of each others company during the stressful period of moving to a new home, and now they have had a day to settle are beginning to sort out their hierarchy! Don't worry, it's totally normal!
Whether boars or sows, all guineas have a herd mentality - someone needs to be in charge, and the behaviour you describe suggests to me that this is what is happening with your piggies.
Other dominance behaviours might include humping, chin-raising, rumble-strutting and waggle-dancing! It is usually best to let the pigs sort out their dominance issues by themselves, so try not to interrupt them. You do need to keep a close eye on them, though. If you see them standing and facing off against each other, yawning at each other a lot or showing their teeth then you need to separate them quickly as a fight is imminent. If a fight breaks out before you can get to them, throw a towel over them and use oven gloves to separate so you get to keep your fingers!
Once they've settled on who is boss you may still see minor dominance behaviour as the boss-pig reinforces who is in charge
Hope that helped a bit!
