I've purchased from MMM three times.
The first time was great, 25 chicks plus a rare free polish. All lived.
Second time, I ordered 50 chicks. They ran out of one breed, and just didn't ship it. Gr. Out of the 4 Polish I bought. 2 were dead on arrival, one just wasn't there, and one died a few days later.
I also lost an EE, a SLW, and a GLW. We called them and the are always very nice and helpful, and have no problems with refunding money. In my case I really wanted the chicks they didn't ship. So we reordered 25. Which we got all free, for the ones they skipped, and the chicks that had died in the previous order. I also got a free partidge Cochin.
All were healthy and alive. Although one was dropped like 3 days later, a very short ammount. And died. So I'm not sure if it was from the small fall, or just the shipping.
Overall I like their business and service, they have lots of breeds. But as I've done chickens longer. I realized their stock isn't the best for breeding. So from now on I will be buying hatching eggs from small breeders.