My mail always comes through the local mail carrier. Anything big, comes through the UPS truck. That is includes Amazon for me. True, very true. There is no way to tell what's in the packages. (Is what everyone assumes, anyways. I've only heard rumors.) The part about no place to house them is only one of the reasons why they need to ship them. The other is that within the first 48 hours, chicks don't need that much. They might be provided with stuff to help them survive, but water can't be shipped with them. The older the chick gets, the harder it'll be on the chick for survival. That's why it's so important. Then for the ones they can't ship- overcrowdedness because of no place to put them. That will lead to unhealthiness, and waterer and feeders that can't be kept up with and possibly a lot of deaths of the chicks. As far as not shipping them out for their safety, it'd be safer not to even hatch them. But how is one supposed to know what will happen in 21 days?