Kills but doesn't eat it?

[cobweb2000]

well i have heard if u cut a little bit of the rats head and let it bleed a little it would do the trick

This is the second time I've heard this. Braining on a DEAD animal is fine, please tell me you are not advising someone to cut a live animal.

OP, I have one snake that will kill her ASF's and then leave them be for a few hours before she eats them. I feed late at night and just leave it in the tub with her overnight -- obviously make sure it's dead first.
Hope she stops being so picky for you soon.