I think you are supposed to wait 24 hrs. The one time I got shipped eggs I couldn't wait and put them in after about 6 hrs. I hatched 6 out of 12. Good luckFinally got in my bantam cochin eggs.. So far so good, no broken ones.. Can't wait to start incubating. Should i let them sit for 24 or 48 hours? They arived in 2 days after shipping