Update:
I am pleasantly surprised by the latest weigh ins. They have been entirely without pellets since 12 March - not intentional, I just ran out and haven't bought any in yet!
Since the start of the Going Pelletless Project, on 1 February, the pigs weights have changed as follows:
Dexter: -60g
Gwenivere: -72g (diagnosed with a heart condition and started medication so despite a large loss prior to diagnosis, her weight is now increasing)
Saffron: -37g
Breanna: -56g
Jasmine: -33g
Willamina:- -16g
Franklyn: -47g
Meghan: -58g
Delilah: -32g
Sophia: +90g (don't ask how!?)
Elijah: -57g
Errol: -104g
Pandora: +50g
Harrison: -66g
Delilah and Sophia had been taken off the pelletless project. Despite being given pellets 24/7 again they ate nothing overnight, and they have also been completely pelletless since 12 March and there's been no weight loss. So, at least for now, they're back on the project.
I'm playing it by ear with every pig, but so far all of them seem so much better off for not being on pellets. They do not miss them, they don't wait for them in the morning any more, and their weight has actually been more stable the fewer pellets they've had. Dexter especially has made an incredible improvement - not gassy or "backed up" at all. The long-standing tightness and tenderness on his underside is gone, I can pick him up easily now whereas before he detested being handled due to the pain from his tummy.
As you've suggested Furries, I am focusing more on natural forages. Many more hay varieties (we're on six at the moment!), grasses and - when the weather warms up - more natural weeds. I cannot give any dried herbs to Dexter although all the others can have them fairly often as more variety and forage. I am hoping fresh, natural weeds won't be a problem for him, I will be growing some along with the grasses I'm growing for them and also they'll be allowed to go out in the garden on the lawn a lot more as the weather warms up.