My hutch she's in is waterproof, but not thermal or not water bottled.
I live with my parents, they said no to hot bottle and said I have a good hutch already.
I can't get a thermal hutch cover either.
So I can get an idea.
How long would she live if she did not have a thermal hutch cover or by water bottle (my last guinea pig chewed it) and outside (no shed) ?
She is in hay but has never had an allergy to it before (always lived in it) and now she is on paper (had cold before then) and is also fine.
She will not cope well without full protection on the hutch and without thermal and waterproof hutch covers (which cover all the sides of the hutch to stop wind and rain getting in) along with extra warmth from a heatpad. They can’t cope with temperatures below 15 degrees. The hutch needs to be fully insulated, weather proofed, kept in a sheltered position and kept warm.
Being just on paper is not a good bedding for an outside piggy, it’ll be damp, paper won’t dry and it doesn’t provide any warmth. Being damp and cold is when piggies get ill. They need to be lots of hay - the whole hutch will need to be filled with hay to help insulate her from inside.
I note you keep saying ‘she’ not ‘they’. Piggies are herd animals and must always be kept in pairs - piggies kept by themselves get lonely and depressed. A young piggy by herself without extra weather protection will get lonely and will be cold.
guinea pigs don’t get viral colds - they get bacterial respiratory infections which require medication and treatment. If their immune system is compromised, which can happen through being damp and cold, then they are much more prone to becoming seriously ill.
as hay is a natural product, it can be dustier some times and not others - just because she’s been fine with it before doesn’t mean some dust hasn’t irritated her in this batch of hay. having a good supply of dust extracted hay is important
Can you not just buy the thermal hutch cover and heat pads yourself? you have a responsibility to provide everything your guinea pigs need to meet welfare requirements