Silver fox dogs generally stop growing when they are about 10 months old. At this time, the dog's body shape and hair are basically formed and will not change much, so the dog must be strengthened before then. Nutrition and calcium to prevent stunted growth in dogs. You can give your dog some egg yolks, chicken breasts, beef, carrots, cabbage, fruits and other foods, as well as some lecithin, so that the hair will be healthier.