they sneeze a lot. some get red discharge from their eyes and nose. differing temperments or unusual lethargy. but rats will sleep most of the day as they are mainly nocturnal animals. but give us more details and we can tell you if its just a normal rat or if its a sign of illness. is it alert when you hold it or sluggish?
my rats are more active at night do you think it is possible to change their sleep pattern?? by stimulating them early evening so they sleep at night? i cant sleep 4 the noise they make also a stupid question but can rats vomit?