Broody hen...day 20

[sadie423]

This is our first time hatching. We have 2 broody hens one is on day 20 today, one is on day 16. Are there any indicators that the eggs are hatching? Do the hens act differently? Hold themselves differently? Would I be able to hear anything....we've only ever had day olds so I am didn't know if all chicks peep so much or if one sitting under their mama are quieter? These are first time moms too....so I wanted to make sure I caught them in time in case they turn out not to be good moms.

Thanks
Sarah