In the caption of the video, the mother describes her baby's crying as pretty, but then goes on to describe her tears as 닭똥 같은 눈물, which means "tears like chicken shit." Some people may think "chicken-shit tears" are pretty, but is that baby really crying chicken-shit tears?
닭똥 같은 눈물 are tears that form around the edges of the eyes into big teardrops that eventually succumb to gravity and fall to the ground, supposedly like droppings from a chicken's butt. However, as anyone who has ever watched a chicken poop knows, a person crying chicken-shit tears would need to have his or her head bowed so that the tears drop directly from the eyes to the ground rather than run down the face. Therefore, since the baby in the video is crying while lying on her back, those tears cannot be "chicken-shit tears."