I agree in that Guinea pigs need to be free (with good fencing,of course)my piggies,rabbits and pet hen,Have full run of the garden 28ft by 25ft,they also have a 18ft by 10ft run with their hutches,yep even the hen has a hutch that i made for her,piggies have a double decker,the rabbits have a very large home made hutch that my dad made about 10yrs ago.The hedging has about 4 fire guards that have been separated and dig 2" into ground.The "pen" has a gate for me to get in and out,also a small door for the pets to get in and out.If there are too many children in the garden(i'm a childminder,but with 2 kids of my own) ,then i lock them into the pen, to keep them save from little feet running around.I use my daughters play house lately for guinea pigs to use,put grids(C&G- fasten with cable ties) around the front like a garden fence and peg down with tent pegs so that Boris doesn't lift it up!But i do need to sort something out for the winter time "run around",they are in the shed in a double decker hutch,until summer. I HATE TO SEE ANY CAGED ANIMAL WITH NO ACCESS TO SOME FREEDOM,HOW WOULD PEOPLE LIKE IT IF THEY WERE STUCK IN THEIR BEDROOM/TOILET ALL DAY!