I think the earliest I ever got them was February, but they were fine, February is largely the same as January here in my experience. They are all in a corrugated carton where there seems to be exactly enough room for 25, body to body keeping one another warm without being crammed tightly together, they could turn around. The post office called me as soon as they arrived, and I drove into town and picked them up. It's really pretty amazing, but the process almost always goes off without a hitch as long as you're ready to put them in the brooder with water and food and a heat lamp as soon as you get them home. I have not brooded day olds in many years, but in the past was I did was set up my light and put a thermometer on a plastic feeder below the light so I could make sure I knew where the light had to be to get around 95 degrees the week before they were shipped, then the morning they arrived I just put the light on before I left to pick them up, and had the waterers and feeders filled, so I just dipped eah one's beak as I removed it from the box, then set it down, and they apparently had read the book on how to be chicks because they immediately would each have a little drink and then start scratching at the food. To keep their little legs from splaying, I covered newspaper with paper towel, and scattered some crumble on that as well as having it in the feeders, and I think maybe 4-5 days later I took up the paper towel and put down a layer of pine shavings. They can get stinky plenty fast if there are enough of them.
When I asked for the third test she asked if I sold eggs, and I said, well no, but we eat them ... 
