Yes they can. Here's a couple of links to some great sites that also have plenty of links to great sites and forums that are all about Cavy's for you :-). Keep up the good work (assuming you asked about feeding your own Cavy).
www.guinealynx.info - they have a great diet section and breakdown
www.cavyspirit.com
www.guinealynx.info - they have a great diet section and breakdown
www.cavyspirit.com