Redwings Horse Sanctuary have issued a warning about fireworks following the loss of two rescued horses last year.
Vets were called to attend incidents at Piggots farm, south of Norwich on November 5 2016.
In both cases the animals had to be put to sleep having been terrified by a nearby fireworks display.
Nineteen-year-old Welsh pony, Sprite, was found suffering with suspected colic, he was lying down, covered in sweat and breathing heavily.
Similarly, Percy, a 25-year-old Palomino pony was found non-weight-bearing lame on his right front leg and in pain.
Attending Redwings veterinary surgeon, Dawn Trayhorn said: “As a result of loud fireworks being let off nearby, it is possible that Sprite’s Colic was brought on by the stress of him and his group charging around in terror. Percy’s injury may also have been caused when he was running around at high speed.
“Heartbreakingly, despite our best efforts, there was no choice other than to put them to sleep.”