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.
counter noun [ C ] (SURFACE) B2 a long, flat, narrow surface or table in a shop, bank, restaurant, etc. at which people are served: There was nobody behind/on the counter when I went into the bank, and I had to wait to be served. You will find sausages on the meat counter/rolls on the bread counter.