Sneezing Guinea pigs acting normal aside from sneezing?

[Seqouia]

All 3 of my piggies have been sneezing more than usual lately. Maybe a few times a day. At first I thought it was just when I put hay in their cage but have noticed it at alll times of the day. They are wheeking, happy, eating, and drinking regularly aside from the sneezing but I am beginning to get concerned. I did a little bit of research and learned that it may be some kind of allergy. They DO NOT live in wood shavings but on fleece washed with hypo allergenic detergent and carefresh. Has anyone else experienced anything similar or have any advice? Thanks in advance!

 

[PiggieWigglies]

Allergies, Im not quite sure what else would make them sneeze, unless they have a cold or a runny or plugged nose

 

[foggycreekcavy]

Is the temp pretty cold where you live? Perhaps the air is too dry from the furnace/heater being on constantly. I bought a humidifier to add some moisture to my rescue room.