Maggen eggs have ears on them! While a brain isn't fully developed to interpret any input language, loud noises can damage a Maggen's hearing later on in their adult life.
Maggens have two heads. One is the actual head where the brain is housed and the second is on the tail. This allows Maggens to see in multiple directions and hear in multiple directions. This is particularly useful if they need to peak around a corner.
Because of these advantages, Maggens are very cunning and can sometimes be deceitful if they are looking to get out of difficult situation. Even if you treat your Maggen very well, they may still deceive you (or at least try to).