But there shouldnt be any drafts, the bigger the group the better (can cuddle together), plenty of hay for them to snuggle in, also fleece blankies and cuddlecups are good, and could you possibly get a heater into the shed? extension cable?
But anyway, you better wait for the experts to come online, I only kept rabbits outside and that was ages ago, so I am not exactly the outdoors-piggy-expert lol
its the droughts that kill guinea pigs put it this way I have recently lost 5 pigs and all since the weathers changed and mine all live in heated sheds no drought blinds at the windows yet I still lose mine around oct nov every year, if you do keep it in the summer house, only do so with heating an oil filled radiator, but low wattage panel heaters are best, and make sure no droughts, add pig igloos they trap heat in them thats why I dont use mine in summer cuddlecups vet bed towels anything to keep them warm,
There are no daughts in the summerhouse,it cost Â£2000
I did have a heater in there last year but the electric bill was Â£800 for 3 months :o
They are a group of 4 piggies i fill the bottom part of the hutch with hay and when i go in and feel them they are warm