John Akrill, 47, was jailed for 20 weeks and banned from keeping animals for life by magistrates' in Scarborough, North Yorkshire.
The court heard how he sent a taunting text message to his ex in August last year saying he was going to kill the defenceless pets.
Later that day he broke their necks – reserving particularly sickening malice for the kitten she liked the most.
He then used a hammer to make sure all four were dead before dumping their mangled bodies in a dustbin where they were found by RSPCA inspectors.
Akrill, of Great Fryup Dale, Whitby, claimed he thought the eight-week-old black and white kittens were suffering from cat flu but an RSPCA vet and the post-mortem found no evidence of any illness.
Akrill had also texted his ex earlier that day threatening to kill the beloved cats, magistrates heard. Let's demand a harsher sentance
GRAPHIC CONTENT: Jilted boyfriend exacts revenge by SNAPPING kittens' necks
we need harsher punishments for animal abusers please sign and share to make this happen,
