Is it normal for a one-year-old male dog to have crusty lump on the back of his testicle?

No, it is not normal for a one-year-old male dog to have a crusty lump on the back of his testicle. This could be a sign of an underlying medical condition, such as an infection, injury, or tumor. It is important to take your dog to the veterinarian as soon as possible to have the lump evaluated and treated if necessary.