My 9 month old has been having hard stools the past week to week and a half, I started her back on her liquid vitamins about 2 weeks ago, assuming possible the iron is making them harder and darker, however yesterday she had 1 dark dark, almost black stool, hard. Today she had two hard stools but they both were blue. She eats prune baby food from time to time and had some last night, but I never remember her having blue stool before, should I be concerned?? No blood in stool , no fever, doesn t seem to express any pain anywhere. Any information would be appreciated, thanks so much!