It is not normal for a 40-day-old kitten not to poop. Under normal circumstances, it is normal for a kitten to defecate 1-2 times a day, or once every two days.

The frequency of defecation in kittens is related to food, eating habits and intestinal absorption and digestion function. If your kitten has not had a bowel movement for more than three days, she may be constipated.