We have two 6-month-old boars. Frisky we've had since he was about 8 weeks, Parcheesi we've only had a few weeks. Neither would eat green or red bell pepper, no matter how persistent we were about offering it.
Then I got an idea. They both love their greens, and especially it seems, the Belgian endive. So we started taking the cut pieces of green pepper and rubbing them on the endive before feeding them their veggies. I figured, putting the green pepper taste onto a familiar and leafy veggie might help them get used to it. It worked!
Not only have they both started eating green peppers, today Parcheesi went and snatched up a green pepper piece as soon as the carrots pieces were gone from the plate!
So... I know many others here have said that their piggies don't seem interested in the green peppers. Try my trick and see if it works for your piggies too!