Greetings, and thank for the question:
Based on what you are describing concerning Whisper, she is experiencing what is known as “choke”, or in other words, she has some feed blocked in her esophagus. Although this is not a severe, life-threatening condition at this point, and is not uncommon, it is something that needs to be addressed as soon as possible.
Quite often, as horse can clear a choke on it’s own, however it is best to have a Veterinarian examine the horse and manually clear the feed by using a tube passed through the nose and into the esophagus. In the majority of cases, chokes are easily cleared, depending on the material that is lodged (such as pelleted grains, etc.). An important reason to have a choke cleared as soon as possible is to help reduce the risk of aspiration pneumonia, caused by the horse accidentally inhaling the liquid into her lungs, introducing bacteria.
I would strongly recommend that you contact Whisper’s Vet ASAP, as the sooner that a choke is cleared, the less chance there is that a complication may occur.
Do not allow Whisper to eat any further food until the choke is resolved, as that can only worsen the situation.
I do trust I’ve been of some help, but please let me know if you have any further questions.
All the best:
-Dan C., DVM.