Depressed Rat

Question
Hi one of my rats Rufus seems to be really depressed and never seems to want to come out anymore. Hes only about a year old and has always been quite timid but he just wants to sleep all the time. he comes out only if i really make him. hes eating but his back seems a bit hunched and he just looks relatively depressed. please help

Answer
Instead of depression, he may in fact be sick with an upper or lower respiratory infection. It often gives rats a hunch-back appearance. Have you noticed any unusual symptoms, nasal discharge, excessive sneezing/wheezing/coughing, 'monkey' noises, etc.?