My Guinea Pig is Snoring?

[raining.ashes]

I already posted on here about my new guinea pigs sneezing, and the general consisus was that they are likely allergic to something within the cage but I should take them to the vets just in case. I haven't been able to make an appointment yet since it's the weekend, but I have been noticing what sounds like snoring coming from one of them at night. It sounds like a soft, almost purr. Could this have something to do with allergies, a more severe problem, or is it normal?

 

[DM030819]

@raining.ashes It's probably all connected to the same issue. I've noticed that if one of my pigs has a URI it's more noticeable at night. It might be because they're lying down or maybe the house is quieter so I notice more.