This guy I know has a female who gave birth to 5 kittens last year. For the first 2 weeks they were doing fine. Then in the 3rd week, they all died within that week. Two of them on Monday, one on Wednesday and the last two on Friday. It was the saddest thing. The vet said that it sounded like cat distemper and there was nothing that could have been done.

Maybe this was the same thing that happened to the 4 week old kittens.

I'm sorry. Rest in Peace little ones.