Is it legal to send human feces thru the mail if the receiver wants it?

This is probably the wierdest question I have ever seen on this site of wierd questions!! No-one would complain as they would not want anyone to know about it.They would just ask you to stop. It certainly is an odd way to fertilise their garden! They could go to the garden shop much cheaper. I wonder how do you ensure it doesnt smell? I wonder why I am taking this seriously?