Mandy,......you got admit, your boar sure does look happy. I love that picture!
We are on clay too and are trying to run a 6 month rotation. As everyone else says, the mud is the issue. Kate, you dont mention where you are.....I am in the east , where we tend tO get less rain than elsewhere, and find that although the clay gets bad, it soon recovers. Having said this I have seen fields that are on a slight slope and then the clay area towards the bottom is hideous.
Pigs lolling around in wet mud won't help them convert their food well, and you also have the potential that they develop foot problems.
you might want to take a look at Katie Thear's smallholding books...she puts forward a rotational system for 6 sows on an acre. Half acre is sacrificed in the winter, re seeded in the Spring. The Other half is split into
quarters with electric and the paddocks are used in rotation, when the grass is eaten, the pigs are moved on to the next bit. Vacant areas are re seeded.
Obviously with this you need to consider, where your ark goes and how you can move it around. It is also much more labour intensive. you need to work out, how easily you can move the pigs around too, thinking that it may be stupendously muddy etc.
6 per acre does sound very very heavy, esp if you are on clay. Maybe it could work with a couple of KK's though???
Weaner wise ..... If you only did these in Spring and Summer, you would find your ground would do better.
Maybe you could just raise these on a half acre, bearing in mind you only keep them for 3/ 4 months. Just do a small batch per year? You could then keep this as an emergency paddock.
I would be very very mindful of where you raise your piglets. You can't have them going on heavily used
ground (parasite issues) so perhaps, having a spare half could be used for their purposes.
I can't see how you could keep your pasture, really pasture. It will go, and if you have pigs you've got to kind of resign yourself to that.