As far as I know they can eat veggies at whatever age they want to...I don't think there is an age limit. Sooner the better! I've read breeders allowing their babies that are 3+ days old to eat veggies with their mom. Your guys didn't look TOO young from the pics, but it's hard to judge size from pictures. Do you have a food scale or anything you can weigh them with? That'll help give a better idea of age. I was told mine was 4 months when I got him, and from his weight he's more like 6+ months!
I would slowly introduce new veggies if they aren't used to eating them. They can get diarrhea or upset tummies from too much variety too soon. I started Vinnie with green leaf lettuce or romaine lettuce for like 3 days, then added small bell peppers, then carrots, etc. Every few days I would introduce something new. They can have about 1 cup (8 oz) per pig per day of veggies from what I've learned.
