Hello, I am a vet and have a GSP and a few pointing labs I chase birds with.
As all the stories show, seizures can have many causes and are often super frustrating for a vet to try to find the cause of. Lots of dogs have seizures and go on to live a normal life. In a bird dog while hunting, I would guess hypoglycemia or electrolyte imbalances being the cause. Think of it like an extreme version of a cramp. As others have said, make sure the dog is well hydrated on gatorade or some other sports drink prior to hunting. I usually mix it as a powder at 50% concentration so it dos not upset the stomach.
If the dog has another seizure, especially while not hunting (or exerting effort) the vet will almost certainly prescribe some sort of anti-seizure meds.
