Feeding my King other snakes

[Eggo]

OK,first time post here,im probably going to pop in now and then,but i just need to ask a question

Ive got a California Kingsnake,that ive had for almost 7 years,and shes almost 4 feet long. today i cought a black racer,and tried to feed it to her,but it was almost as big as her,and she didnt kill it,she just wrapped around it,and then after a while of it not dying i separated them. I was wondering,if i were to find a Pygme Rattlesnake,would i be able to drop it into her cage,and sit back to watch the show? or does not being wild remove the anti venom from there system,or make them not "remember" how to hunt them?
She attacked the black racer,and constricted it as if it were a mouse,but it was so skinny,that i would have been supprised if she did kill it. sorry i didnt search,ill go do that now
Thanks alot

~Eggo~