The two boys are young and medium sized. It looks like they're being kept in tanks--this creates poor circulation and can lead to a toxic environment over time. Shelters have to make due with their poor funding, it's a great reason to donate! (And of course I may be wrong, I mean no disrespect to the good people at VBACB).
The female guinea pig is a beautiful young girl of medium size. So adorable!
Many sad accidents or "accidents" can be avoided this way. *
helpful links: Quality Hay and Pellets in bulk & Pampering your Pig & Cheaper, Larger Cages & Bedding & Essential Guinea Supplies & Proper Diet & Cavy Savvy Vets & "What's Normal? What's Not?" & Social Life & Boy or Girl? & "What is Rescuing and Adopting?" & Social Cause Marketing & Guinea Pigs in PA/NY/NJ/WV .