If there are both males and females around, courtship behaviour will take place.
In the past the normal state of affairs has been that most males hibernate earlier and come out of hibernation earlier. The females who have had to put on condition after their hoglet duties have finished, hibernate and come out of hibernation later – it could be as much as 2 months difference. That used to give the males the chance to build up condition after hibernation before the arduous task of tearing around seeking for females and rolling up other males, etc. So it all worked out quite well. In those circumstances, courtship behaviour, in general, would have started later – due to the relative absence of females.
There were probably always some females, who did not produce young for some reason, who hibernated earlier – having not had their energy taken up by providing for hoglets, which would have enabled them to put on condition for hibernation sooner.
But, it seems things are changing. Possible reasons are: Those female hoglets who decide not to hibernate may be able to grow sufficiently through the winter to become interesting to the males earlier; It may be that some adult females are also choosing not to hibernate; But also some of the over-wintered hogs may be released earlier, i.e. once people have started seeing hogs around, who have emerged from hibernation, and the weather is better. Any female hoglets would likely still have continued to grow in captivity and likewise, may be interesting to the males earlier than they otherwise might have been. But there may also be adult females who have been over-wintered, etc. due to sickness or injury that may be released earlier. It is stressful for hogs in captivity, so it is understandable that people would want to release them back to where they came from as soon as possible.
But these are possible ways that our behaviour, in our attempts to help the hogs, may be changing the behaviour of some hogs.