Greek Gods Dying?

So I read this book as a teen and can't remember the name or a bunch of the plot. But I know that the Greek Gods are all falling I'll to a mysterious curse and are fighting each other. Each of them are dying based on their specific traits. I.e. Ares has all his battle scars reopening, Athena is slowly turning into an owl, Hermes is starving to death because his metabolism is going at 10000x speed, ect.