Need Cluck Info.

[Aw-Ee Chicken]

Hi, I also have questions about finding clucks: truthfully, what really is a cluck? Is it a hen that frequently visits the nests everyday but still doesn't sit in the m 24/7? Does a cluck make odd quiet little noises while she's sitting but still can be obnoxiously loud when she's outside? What breeds are recommended?
Any further info. along with this would be appreciated. Thanks so much!!!!!!!!!!!!!!