A hard, rock-like tummy could be a sign of several serious conditions, including:
* Constipation: This is a common issue in dogs, especially smaller breeds. It can be caused by a lack of fiber in the diet, dehydration, or a blockage in the intestines.
* Bloating: This is a serious condition that can be life-threatening. It happens when the stomach fills with gas and twists, cutting off blood supply.
* Foreign body: If your dog has swallowed something that's not digestible, like a toy or bone, it could cause a blockage.
* Inflammation: Inflammation in the intestines (such as from pancreatitis or inflammatory bowel disease) can cause a hard, painful tummy.
Please note: I am not a veterinarian and this is not medical advice. You must consult a veterinarian immediately to diagnose the cause of your dog's hard tummy and receive proper treatment.