Neutering, from the Latin neuter, is the removal of a non-human animal's reproductive organ, either all of it or a considerably large part. The male-specific term is castration, while spaying is usual
Feline uterus
Closed spaying incision on a female dog, taken 24 hours after surgery
Surgical incision site of a female cat
Closed castration incision on a male dog, taken 12 hours after surgery
A capon is a male chicken that has been castrated or neutered, either physically or chemically, to improve the quality of its flesh for food, and, in some countries like Spain, fattened by forced feed
Neutering
…used in animal husbandry and animal fancy for neutered (castrated) animals: barrow Pig castrated before maturity. bullock Male castrated draft animal. capon Male castrated chicken. gelding Male castrated horse, or donkey. gib Male castrated cat, or ferret. havier Male castrated deer. lapin Male castrated…
Live capons in Hainan, China, displaying characteristic small head, comb and wattle
David Rijckaert II, Still life with a lemon and capon
Capons in a French market
2257 Salzburg St Peter's Stiftskeller Brust vom gebratenen Capaun auf Gemüse aus Pater Priors Garten mit Sterztaler und Erdäpfelbirne an Salbei Trüffelrahm