The answer to that is 21 days exactly, although you need to bear in mind that this can vary, depending on a number of circumstances. Generally speaking however, fertile chicken eggs which are hatched out by a hen will take 21 days before you see little faces staring at you from underneath their mamma's wings.
In linguistics, a register is a variety of a language used for a particular purpose or in a particular social setting.
Definition of REGISTRAR: An officer who has the custody or keeping of a registry or register. This word is used in England; register is more common in America. The Law Dictionary Featuring Black's Law Dictionary Free Online Legal Dictionary 2nd Ed.