Performances of deep sleep in dogs:

1. Stillness: Dogs usually remain still during deep sleep, with no obvious body movements or very slow movements.

2. Relax muscles: When a dog is in deep sleep, its muscles will relax and its body will become relaxed and will not be as tense or stiff as it is in the awake state.

3. Stable breathing: When a dog is in deep sleep, its breathing usually becomes very stable without much change, and is usually slower than when awake.

4. Reduced eyeball movement: When a dog is in deep sleep, eyeball movement will be reduced and the eyes may be closed, but the eyelids will still tremble slightly.

5. Not easily awakened: When a dog is in deep sleep, its reaction time is relatively slow and it is not easy to be awakened by external sounds or stimuli.

6. Snoring. Dogs will snore when they are deeply asleep, and they may even snore loudly, which can be called a noise maker.

Signs of a dog not sleeping well:

1. Extremely quiet. The dog is mentally weak, physically and mentally exhausted, has no energy to do anything, and does not have enough energy to play. Instead, it will become quieter.

2. Memory loss. If your dog doesn't sleep well, his memory will begin to weaken, and he may even forget the door when he goes out.

3. Inflexible response. Poor sleep quality in dogs can also cause them to be sluggish, easily distracted, and unresponsive.

4. Appetite becomes smaller. If the dog cannot get enough sleep for a long time, the dog's physical condition will decline and his appetite will become smaller.