Update: Clover has had a quick health check and her tummy is fine, soft and flabby and not painful, breathing fine, walking fine, her previously broken leg (which I check a lot) is fine... but there is an ear bite!
I think it's a miltary style coup for leadership by Blodwen because as soon as Clover was removed from the cage and placed in a big box of hay, grated sweet potato and bite size cucumber pieces, Clover relaxed a lot and started eating really gratefully like she's been starved all day (Clover is normally very skittish and suspicious about even taking treats away from the others) and Blod started charging around rumbling and mounting and seriously humping all the other piggies, Piggle's face got humped for a good 5 minutes and Piggle is normally quite dominant! We are going to keep Clover in a box for observation for another half hour but she is definitely eating fine away from her "friends" (Looking at you Blod the betrayer! I hope this is just a strong season because Theo got a nose bite on Wednesday too! And you look so innocent!).
Bloody piggy soap operas! Thank you everyone for your support, I was really worried this was a serious health thing, but I think it is just extreme piggy lady politics... though of course I will keep an eye on things in case Clover is really ill and that is what has prompted this herd boss takeover bid from Blod... but Clover has eaten an amazon delivery box full of hay and about 2 days worth of veg in the past half hour so I dont now think it is immediately life threatening