A dog biting its own legs may be caused by parasites or skin diseases, or it may be caused by boredom. It is best to check whether there are parasites, redness, swelling, dandruff, or peeling on the legs. , scabs, etc. If there is, then it is skin itching caused by parasites or fungal infection. You need to deworm the dog in time, and use anti-fungal ointment on the affected area; if not, then the dog is bored, and you can prepare toys for the dog. Divert your dog's attention.