1. Malnutrition: Dogs may lack some nutrients, such as calcium and phosphorus, which may lead to abnormal eating behavior. Eating bricks may be to supplement these elements.

2. Play behavior: Some dogs will chew all kinds of things, including bricks, out of curiosity or play mentality.

3. Anorexia: Dogs may lose their appetite for some reasons, and eating bricks is an abnormal behavior.

4. Mental stress: Dogs may have anxiety or stress due to environmental changes, loneliness and other reasons. Eating bricks may be a way to vent or relieve stress.

5. Disease problems: Some diseases or digestive system problems may lead to abnormal appetite of dogs, including eating non-food items such as bricks.