I would be more concerned about the beak and talons of an angry rooster! It would make sense to me that the comb could turn deeper red as the rooster becomes angry due to increased blood circulation. I have never heard that the comb is poisonous, though.
absolutely not, it is a gastronomical delicacy. You know that funny little red thing on the top of a rooster’s head? It’s called a cockscomb, and as Francine Segan recounts for Gastronomica, it’s very tasty:
A rooster's comb is not poisonous. The red color is a visual marker, as are most colors on male birds. They are used to identify one another and for communication (to warn each other away, for instance). A comb may flush a deeper red when the bird is agitated simply because when an animal (or even a human) becomes excited, the skin will blush. This is not special to roosters.