When can we start putting a pillow behind our LOs heads when they sleep? Are there any pillows that can help prevent flat head?

It is not recommended to use a pillow for babies under the age of 2. Even older kids don't need pillows. Some parents find that their children sleep better with pillows when there is congestion, but the pillows can be placed under the mattress to create an incline instead of directly below the child's head. If you really want to, opt for a firm pillow instead of a soft one. Babysafe is a popular brand. http://www.babycenter.com/404_when-can-my-child-sleep-with-a-pillow_7533.bc