When you've been marrying your cousins for 35 generations problems can arise.
My historian pals blame the Black Death for this. Of course, intermarriage also sometimes increases the IQ - check the history of Ashkanazi Jews and my field of interest, the Plantagenets.
I don’t really know why they are so nutty about animal deaths. They wanted the American guy who killed Leo the Lion dead, dead, dead last year. There’s a screw loose somewhere.