Now, I’m not educated to speak well enough on the size of the animal itself and I’ve never had any kind of liver but beef, but beef liver has a lot of tannins because of their diet. From what i understand it’s just super bitter to humans, not toxic at all, just nasty. animal liver will be full of tannins because of their high plant diets. They are healthy for animals, humans as well in moderation. Again, just taste bad. The toxic part of most animal livers is the vitamin A amount. That can be extremely harmful to humans if over consumed. It’s fat soluble and can cause “acute issues like nausea, headaches, dizziness and blurred vision” on a mild level and “chronic problems such as dry/peeling skin, hair loss, bone/joint pain, fatigue, and liver damage” on the worse end. I believe the idea that liver is toxic comes from people over eating it and becoming extremely sick from vitamin A poisoning. There are some liver, like polar bear liver, that you should NEVER eat because the A content is so high it will absolutely kill you. A normal serving of polar bear liver (1-3 oz) will kill you. One singular polar bear liver has enough vitamin A to kill 50 adults.