My pigs aren't fussed on carrot (love carrot leaves though) but will eat it if it's all I give them - cue many judgey looks and outraged wheeking
Current Bun loves his evening carrot and sometimes carries it around with him so he can eat it in his basket. Previous Bun would never touch carrot, apparently it was evil. She loved the leaves though and always had some for breakfast.
70 Current Bun wears Real Fur and he keeps leaving large amounts of it on us - we think he's trying to get us wear Fur as well. He won't win.
My guinea pigs I had as a child used to go mental for melon skin (we ate the flesh and put a small amount of skin in the run) might be worth a try, without the flesh they won't get the runs, ours never did.
Funny little souls aren't they..... mine would mysteriously 'go off carrots' and I wondered if they were just too big for them to cope with, tried cutted up ones, they wouldn't touch them. They must love the sensation of ripping into a big carrot to keep their teeth sharp and busy, and not actually swallow the flesh they have bitten - a friend used to bring ours cabbage leaves, organic, grown on his allotment, sometimes they would be devoured like it was the last meal on earth, and other times it was ignored, peed on and left to go off < vile cabbage smells errupting from hutch>.
At primary school my kids would bring their friends home and the guineas were a great source of entertainment, up and down the stairs, herding them round the garden, cuddling them - the guineas loved being the centre of attention. I could often be spotted on rainy windswept days ( of which there were many!) out with my binbag filling it up with grass and dandelions ready for the gang to chomp.
'See you're out again!' neighbours would shout ...'they must be hungry'. No. they are greedy little monsters who can devour a binbag full of grass in less than a day!!