So a few weeks ago my 7 month old daughter had very very dark green poop, basically black and I took away the rice cereal she was eating. And after I stopped her poop went back to a normal color. I got some more last night to try again to see if the rice was the cause of it and today she had the same dark colored poop and I get it to her last night. It happens with oatmeal as well. Could it be to much iron? She’s on nutramigen formula if that matters. Should I mention it to her dr?