Here's my few cents on the comments written on that page.
The question of "Don't the cavies jump out." is definitely the most common question asked when people visit my caviary. And the answer is "No" They seem to know their limits and have no desire to leave the security of their cages although they do like to "hang out!" (Quoted from the site)
They don't jump out because the glorified litter boxes they live in have killed any will and skill the animals might need to jump out. The fact is, with that amount of room, they won't be fit enough to jump out, even if they wanted to.
They don't even have a house to get away from it all - apparently because "there was not enough room to deliver" babies. It's a pity she didn't re-assess and decide that it might have been the overall space that was the problem. To put a house in those cages would be like trying to fit a human in a cupboard in a cupboard (yes, that was intentional). "They can not be as easily observed for signs of illness if they hide in houses" - so the way that they are assessed for illess is how they behave in their cage? "Houses can trap ammonia fumes" - only because with a cage that size, the cavies have the joy of lying in their own urine and faeces all day long. They have no option to choose another area as their toilet corner.
"Wooden stove pellets" are used as bedding. Most people who own a wood burning stove or open fire in their house will know that these often have wood oils added for that authentic fire smell.
On the other hand, the cavies look healthy. If only looking healthy were everything.