In a group of chicken eggs how do you know which are fresh and which are old?

To check the difference between a fresh and a spoilt chicken egg , you first need to do the following steps : 1) Put the egg in some water . 2) Heat it for about 2minutes or more , but remember ! not to let the water boil . If the egg floats on the water it is fresh , while if it sinks down it is a spoilt (old) one.