Signs that your horse could need a check-up:
1. Dropping food while eating, difficulty chewing or excessive salivation.
2. Loss of body condition.
3. Large or undigested feed particles (long stems or whole grain) in manure.
4. Head tilting or tossing, bit chewing, tongue lolling, fighting the bit or resisting bridling.
5. Poor performance, such as lugging on the bridle, failure to turn or stop, even bucking.
6. Foul odor from mouth or nostrils, traces of blood from mouth.
7. Nasal discharge or swelling of the face, jaw or mouth tissues.
I hope this helps. Sorry if there is any spelling mistakes.