I know almost every member here is against guinea pigs living outdoors. But me and my father have been looking at it from every angle, and we think it is the best choice. I have several reasons.
First of all, if they were to be kept inside, the cage would not be big enough for them. We don't have that much space in our house that we are willing to use for the guinea pigs.
Second, all of your arguments about why guinea pigs should not live outside are countered in our situation. Weather. The way the hutch is going to be insulated and positioned, rain won't get in, the time in the sun is minimal, and the nights will stay around 70 degrees, as will the days. I live in southern california, so the cold weather is minimal, and keeping the temp low enough for the piggies won't be a problem.
Also, the cage will be about 2 1/2 stories (2 stories, and then a 3rd story that wont cover the entire cage, but about half of it). Even if the pigs decide not to go up the ramps at all, they have a 16 sq. foot cage on the first floor alone. Adding up all the floors, if we have adventurous cavies, they will have 40 sq. ft. to roam in!
As for the issue about not getting enough attention. It is sort of hard to miss a 16 sq. foot cage that is 3 stories high. We have a clear glass door that goes into the backyard from the kitchen/living room area. If the guinea pigs as much as squeak, we will hear them.
Predators. First of all, we live in suburbia, so the wild animals are minimal. We don't see outdoor cats that much here, but we do occasionally get coyotes. The cage will be raised about 3 feet off the ground, and we will add padlocks to the wire mesh door. And it's not flimsy, its very solid. That is even if there are any coyotes, as I have personally never seen one in my 16 years of living in this house.
If you have any other arguments I missed, please tell me. Otherwise I think my future piggies will have a happier life outdoors then they could ever have indoors.
One last note. Unfortunately, I probably wont be able to adopt guinea pigs. We have a local adoption agency in our area (Orange County Cavy Haven) but they are against outdoor living too. So I guess I will have to buy from a pet store. I wish this was not the case, but it is.