Which of the following is a sign that a dog may have ticks?

Scratching or biting at the skin is a common sign that a dog may have ticks. When ticks attach to a dog’s skin, they can cause irritation and discomfort, leading to the dog showing signs of distress by scratching or licking the affected area. This behavior may also be the dog's way of trying to remove the tick or alleviate the itchiness that results from the tick's presence. Observing a dog engaging in these actions can be a clear indicator for groomers or pet owners to check for ticks or other parasites.

In contrast, signs like increased appetite, loud barking, or frequent urination are not typically associated with tick infestations. Increased appetite may suggest other health issues, loud barking could be a result of various triggers unrelated to ticks, and frequent urination might indicate a separate medical concern such as a urinary tract infection. Thus, pinpointing scratching or biting as the behavior related to ticks directs attention to the appropriate issue, reinforcing the significance of observing a dog's skin and behavior during grooming and care.