Chins sleeping day and night

[klebbing]

We have 2 chins, and have noticed that they are now sleeping both day and night. They are normal in every other way. Not lethargic when wakened, normal poop, etc. Should we be concerned? Also, eating and drinking about half as much. This just started a couple of days ago.

 

[Stackie]

Is the temperature in their room different than usual? Any other environmental changes?