If they are from China, I wouldn't be surprised.
People are dying from bird flu over there, at least 8 people that I know of this year.... and seeing as the Chinese are not very known for being open about things like this, there are probably a lot more people dead than that.
Edit: I've checked around a bit, seems that this has been happening for a while. You guys are not the only ones that has had this happen. Whether it's human death related or just dying birds, I guess the fact that there are lots of free roaming poultry means that if the package was sent from some place found infected, it might be quarantined.