After giving birth is it normal to bleed when pooping?

Sometimes. During labor, especially when pushing, you can cause hemorrhoids to worsen. If you have internal hemorrhoids then can bleed easily when you have a bowel movement. You should check with your doctor to see if you have internal hemorrhoids as there are medications which can help.
Rectal Bleeding. Description based upon info given sounds like bleeding from hemorrhoids. See your local physician for confirmation of this & treatment recommendations. Enlarged hemorrhoids is not uncommon in pregnancy.