Sorry for your problems. If they were sexed, you would think that they would catch the curled toes and not ship them, but if they are quickly grabbing straight run chicks off a conveyor belt and putting them in a box, it might not be as noticable as you would think. Curled toes is probably a genetic defect and the spraddle legs is probably a physical accident. I think it is strange that you would get 4 in one shipment. With some hatcheries shipping over 100,000 chicks a week during the busy season, you are going to see some problems, but what happened to you sounds like bad luck. If McMurray or anyone else shipped that many injured or misformed chicks regularly, they would be out of business.
The weather this time of year can be hard on shipped chicks. Even if you are in a fairly warm area, you don't know what route those chicks actuallty took to get to you. You'll see the number of posts about chicks having problems during shipping go up this time of year. Some post office employees are pretty good about handling chicks and some are not. Just a fact of life. You'll also see a spike in the number of posts about shipping problems right after a holiday. Despite how things are supposed to work or how they should work, a lot of post office employees take time off at the holidays and things just don't go as normal.
I'm not saying your problems with the sick chick is due to shipping. I've had chicks I've hatched not make it through the first 24hours. Some just are not equipped to make it. As others have mentioned, keep it warm and feed it liquid and food. It may make it and it may not.
As an aside, unless you have a really compelling reason to breed it if it does make it, a chick that had those problems would not make it into my breeding flock. I'm not saying to kill it. There are plenty of other reasons to keep a chicken other than breeding, but I would not want those weak genes in my flock's gene pool.