cigarman: The airline doesn't have to carry animals - it opted to and by doing so agreed to abide by the Animal Welfare Act, which spells out exactly what they must do for animals. That act covers numerous things, including minimum and maximum temperatures the animal may be subjected to; how much ventilation it must be provided; how secure the pet's carrier must be to contain it securely so it can't get out; and it states over and over that all this must be done so that the animal is kept safe and suffers no harm or distress. It specifically says the animal's individual carrier must not be dropped or tossed. If CO doesn't want to carry animals, it doesn't have to. But when it choses to, there are regulations it must abide by and in this case it appears to have failed.

(I put a link to the regulations on the first page and noted the specific ones that apply, in case you're interested in reading them.)