Well, I don't eat animals and I am opposed to the culture that says that it's okay to hunt and kill them for pleasure. However, the reasons I don't eat animals are that eating meat is unhealthful for the humans who do it and diverting protein foods from human consumption to animal consumption deprives the underclass of humans of food so that the upper classes can have meat to eat.
In my opinion, the best argument for you to use is that you are arguing for the *humane treatment* of all animals. While they are living, farm animals should be treated well; provided feed, water, shelter, and clean living quarters; and transported from place to place in a humane manner. The means of killing farm animals for food should likewise be humane (and often it is not), avoiding creating fear or pain, and not wounding (rather than quickly and cleanly killing) an animal in the process.
As far as woodland and other wild animals, if hunting is permitted, it should be done within the parameters of the law and "good sportsmanship." Again, avoid wounding an animal and leaving it to experience pain and a slow death.