Yesterday I was making some duck liver pate at home (yum!) and put some scraps of raw liver into the dog's bowl at dinner time. She's been raw fed her whole life (2 years) and has never rejected any kind of raw meat, but she left this entirely - actually ate around it and left it there!
She eats beef, lamb and chicken liver, so what is it about duck liver that's objectionable? It's making me suspicious about the (rather tasty) duck liver pate that's now in the fridge...!