We have 9 eggs on day 21 this is our first time hatching and we have a few questions, should we hear them in the egg shell peeping loudly before they hatch? how long does it take for them to hatch once they crack the shell. We think we may have twins in one do they need help or do we leave them alone? any and all advice would be nice because i am excited,nervouse and want to make sure i do this right