My 3yo niece has developed a weird new habit. She liked to chew on her hair. Is this normal?

If your niece was only twirling the hair, it would have been alright. However, chewing hair can also signify a condition known as pica, which is a form of some deficiency, mostly zinc or iron deficiency. please consult with a doctor immediately. even though there are no tests to determine if it's pica, it will highlight any deficiency. also, hair strands can get stuck in the system and cause serious health issues. the doctor will also recommend tests to look for the same. http://www.livestrong.com/article/321173-why-do-babies-try-to-eat-their-hair/