Noisy chickens

[indianna73]

Does anyone know why chickens make so much noise after laying an egg? I'm sure i would make a lot of fuss too if i had to pass an egg but wondered if there is another reason for this.

[Clanad]

One site says studies suggest that the hen cackles after laying an egg to signal to the rooster that she is available for mating. They also point out, however, hen's cackle other times as well...