Last year, I ordered 8 chicks and all arrived healthy, peeping, and active. No deaths, no illness, and no injuries. When one *turned* into a rooster suddenly (
), MPC was cordial and efficient in doing their best to right the incident. I ordered again this year, to replace the rooster and one hen who passed of probable heat stroke, and received 4 living chicks just yesterday. One had a broken toe and 3 had pasty butt, which I'm still trying to fix. I'm not quite sure if this is something I'm to inform them about, but I will definitely be checking the website. Even so, if I need more chicks, I will still choose to order from them.
When choosing a hatchery, consider quantity and quality. If you want quality for showing, you must go breeder. If you only want a few chicks for your backyard, or less that 25 in general, you can choose a breeder (in case you're particular about breed and a possible showing future or if you just want to guarantee egg color.), your feed store (usually the chicks are sold straight run, but you get your choice out of a large bin full of chicks), or you can go MPC, which sells as few as 3 standards or 5 bantams. They have far more happy customers than unhappy ones, and I can't ever recall seeing a single post about MPC sending dead chicks.
There are many other big hatcheries, but their minimum chick size order was about 3 times how many I was willing to keep, and they often add in "packing peanuts"(roosters to keep the others warm). If I've provided any false or inaccurate information, I'm sure BYC will correct me, as this site is full of knowledgeable people who have a lot more experience than I do.
Best of luck and I hope you're happy with whichever route you choose!