Is it normal for a six year old to poop every two to three days?

Common, not normal: Stool retention is an unfortunate pattern that a number of kids develop.Aggravated by diet, unwillingness to come in from play when nature calls, unwillingness to go at school all add up.The pattern self perpetuates. Increasing fiber in the diet, avoiding constipating foods, increasing fluid intake can help as will daily scheduled emptying.A workup at your doc is a good starting point for recovery.

Yes it is normal: Bms every 2-3 days is still a normal pattern. Continue to encourage your son to eat a variety of fruits, vegetables, whole grains plenty of fluids especially water. If he is having increased pain passing bowel movements consult with his pediatrician.