We would surgically remove the testicles and the bird was refered to as a Capon.. In the early 1950's we would insert a pellet of diethelsibestrol [sp] which is a female sex hormone under the skin of the neck of the bird. this would have the same effect to fatten the bird for sale. the problen was in many cases the pelet did not disolve. many people bought chicken necks for food and who ever ate them male or female would get adose of female sex hormone.. Not a good idea....