It sounds like two males. The more dominant one biffing the other one out of the way. They often do that and sometimes roll them along for several yards! It doesn’t seem to make any difference whether there is a female around or not.
Courtship behaviour involves the female backing away and huffing and then the male begins circling her and she goes round in circles as he does so. She will occasionally give him a biff but usually not nearly as aggressively as a male will to another male.
You are lucky to have had three hogs. Not sure whether you meant all at once . It isn’t really unusual, although if they are males you often find one of them rolls the others up and this time of year they are quite likely to start the courtship circling if one is a female. If the third one is still quite young (male) and not perceived to be competition, it may get away without getting rolled up. It depends a bit on individual males. Some males will run off if they realise another male is there.
Occasionally there is a ‘grumpy’ female who will biff another female out of the way, but again that is usually not as aggressively as two males are likely to be.