Actually, avidin is not toxic, but it binds biotin, so an animal fed nothing but raw eggs will end up deficient in biotin. Avidin is inactivated by heat. However, many species of wild animals, including wolves, coyotes, and foxes, will eat eggs when they can get them as they are such an excellent source of high quality digestible protein. Even animals we consider herbivores, such as deer, have been observed eating the eggs of ground-nesting birds.
Unless you are feeding a diet of nothing but raw eggs, avidin is unlikely to be a problem. The amount of biotin inactivated is approximately the amount the egg contains. I do feed my dogs a raw egg or two every day and have done so for many years without a problem. Many people worldwide have fed raw eggs to a very wide variety of species.