  Since a bunch of people inquired, here is the article from the 
guinea pigs magazine:
  Here's the article:

"ARE THE OUTDOORS SAFE FOR GUINEA PIGS?"
 
  When Jackie Duboux and her family moved into their new home 
in California, she thought the expansive front yard would make a 
great playground for her Peruvian guinea pigs, William and Harry.
"We thought, how nice, we could let them go out on the lawn, and
run around, and eat the grass, and get a little sunshine", she said.
So they made an outdoor enclosure for them out of storage grids
and let the pigs loose for supervised outdoor playtime. The pigs 
grazed on the grass, soaked up the sun, and breathed some fresh 
air. Being responsible guinea pig parents, Duboux's family made
sure the grass had not been treated with chemicals, pesticides, or
fertilizers, which can be deadly to animals. 
  One day, William got sick. Really sick. "We nearly lost him",
Duboux said. "The second week we moved in here, he was so 
deathly ill. He had to be on antibiotics and hand-fed every day for 
two weeks. He wouldn't eat."
  The veterinarian told her that it was probably an E.coli contamin-
ation. "What didn't occur to us is that guinea pigs can get sick if
they're eating grass that has been contaminated by feces from
dogs or cats or other wild animals," she said. "We have deer in 
our neighborhood, and they regularly come up in our yard." 
William got sick from eating grass where the deer had been poop-
ing. Duboux does not let her guinea pigs out in the yard anymore
because she can't be certain some wild animal hasn't been there.
  Wild- and domestic- animals threaten guinea pigs in other ways
too. Stray cats, dogs, turkey vultures, red-tail hawks, and raccoons
can snatch these pets in the blink of an eye. That's why Kurt Nak-
amura, DVM, of Adobe Animal Hospital in Los Altos, CA, stressed
supervision. "If someone can do that- have an outdoor area as
long as it's supervised and safe- it's a good thing," he said.
  The pigs must be kept out of direct sunlight. Cold-tolerant and
heat-sensitive, guinea pigs can develop heat stroke at temper-
atures exceeding 79 degrees Fahrenheit. (Heatstroke can occur
in lower temperatures if the humidity is high.) The optimal tem-
perature for guinea pigs is 65-79 degrees Fahrenheit. 
  "In summertime, especially, there is a higher risk of overheat-
ing," said Nakamura. "If they are already warm and you have 
them in the sun, it's going to make it a lot worse."
  If you decide to let your guinea pigs run free in an outdoor
enclosure, Duboux recommended placing the secure enclosure
in a shady spot, providing plenty of fresh water, and keeping an
eye out for predators. "And never leave them unattended," she
added.


***JAIME***, Molly the new pig in town! & Albert always in my heart.
http://www.piggiepages1.blinkz.com/ 



