" The males of some breeds of chickens such as the Old English, Modern, and American Games, are required to be "dubbed" in order to be shown. These are all single comb breeds. "Dubbing" consists of the removal of the head appendages such as comb, wattles, and ear lobes. This is similar to the dockin of tails on certain breeds of dogs. This procedure is usually conducted using surgical shears and takes place when the males are six months of age or older. These appendages do not grow back so it is only necessary to perform the procedure once on each bird. "
" Single: A moderately thin, fleshy formation of smooth soft surface texture, firmly attached from the beak along the top of skull with a strong base, the top portion showing five or six rather deep serrations or distinct points, the middle points being higher than the anterior or posterior, forming a semi-oval when viewed in profile. The comb always erect and much larger and thicker in male than female; may be lopped or erect in female, depending on breed. The comb is divided into three sections, the front or anterior, the middle, and that extending past the rear base of the skull, the posterior or blade "
" Pea: A medium length, low comb, the top of which is marked with three low lengthwise ridges, the center one slightly higher than the outer ones, the top of which are either undulated or marked with small rounded serrations, a breed characteristic found in Ameraucanas, Brahmas, Buckeyes, Cornish, Cubalayas and Sumatras. "
From the side , that single comb viewed from a distance looked like a pea comb . The OP stated its a fallen single , and the last picture shows a damaged example of a single comb IMO . I don't understand why two game breeders would call it a pea comb , but I'm not a game breeder .