how old r the chicks when they are shipped and is it dangerous for the chicks to be with out food or water or on a plane?
When they hatch they absorb the yolk. They can live off of that yolk for over 72 hours without eating or drinking. That's why I mentioned they are hatched in a certain time period, so they have enough yolk left so they can live while being shipped. They are just hatched, just a few hours old.
The risk is obvious, sometimes airplanes or ground transportation is delayed. You never know when a tornado or blizzard will disrupt transportation so try to order during better weather times of the year. And avoid postal holidays. You can notice an increase of posts on here about shipping problems right after a postal holiday.
They have been shipping chicks in the mail for a long time. They have procedures and methods to make that as safe as they can. For instance, airlines are not allowed to ship chicks in the same cargo hold with anything in dry ice. As the dry ice melts it releases carbon dioxide which can smother chicks. They have rules in place to prevent that. The system works really well but nothing comes with an absolute guarantee. Your trip to the grocery store doesn't either. You never know when someone will run a light or stop sign and cause damage. That doesn't stop you from going to the grocery store.
Usually rural king and tractor supply don’t sell Cornish cross or I always get there too late
Talk to them. Sometimes they will order chicks you want for you. You just go pick them up when they come in. Not every tractor supple or rural king will do that for you but some do. It doesn't hurt to ask. Many people do this to get around minimum number of chicks in mail orders from a hatchery or to avoid the inconvenience of running to the post office when they call.