Ponies which graze on a nature reserve are set to be shot with a tranquiliser gun so that vets can examine them.
Dog walker Penny Richardson complained to the Norfolk Wildlife Trust about the state of one of the animals, which are on its Roydon Common reserve, near King's Lynn.
She said it was infested with ticks, adding: "They just need treating and giving a proper home if someone's not looking after them."
A picture shows one of the animals' ribs showing through its coat.
A spokesman for the wildlife trust said: "There are three very old Exmoor ponies grazing on an area to the north of NWT Roydon Common. These wild ponies are not owned by the trust, they are being grazed by a commons rights holder.
"In consultation with the RSPCA and with the owner's permission we have arranged for a vet to visit who will be darting the animals to enable their treatment."
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