Oh for the days when you could give kids like those a swift kick in their arses.
About 10 years or so ago we had 2 such 'children' in our neighborhood and every home copped stones throw on their roofs, graffiti sprayed on fences, mail stolen from mailboxes, etc, and even car tyres let down or spiked.
The mother of these 'sweet, little darlings' was less than useless as a parent so we all contacted a well respected, retired Policeman.
He spoke to the Magistrate on our behalf and quite unexpectedly go an Exemption from Prosecution Under the Child Abuse Act, presented a copy to the mother whilst accompanied by 2 uniformed Officers, then proceeded with giving each 'child' as swift boot up their arse and then informing them that they WILL BE working in every yard of EVERY house in the neighborhood for a minimum of 20 hours per house cleaning gardens, removing weeds and ANYTHING the Homeowner deemed they should, they would receive 1 cup of cool water for every hour of work, 1 slice of bread and 1 piece of fruit SHOULD they be working at lunchtime and they WOULD be required to carry with them a notebook that each homeowner would sign WHEN they started and WHEN they finished each day.
Failure to do so would mean that the 'child/children' WOULD be placed for 12 hours per day, every weekend for 4 months in Juvenile Detention.
The 'mother' also got written Court notice to 'Clean' up her act as a parent, seek help with her drinking, etc, and that a Court appointed Inspector would be checking on progress BUT at irregular times and dates.
Within 12 months we all went from a neighborhood of almost absolute chaos to a very nice, peaceful, friendly one with those 2 children becoming model citizens.

I'd purchase a cc camera and alarm system.

bb gun.

I would warn the parents that if the boys do any more malicious damage that you are aware of, you will report them to the police. Maybe the parents will then get serious about controlling the boys.

I'm sorry. I might move.

Call the Police - call Child Protective Services (CPS). (Gender has nothing to do with my answer btw).

Unless you know the parents well and can have a sit down with them and discuss it. This is well out of hand.

These kids need some handling now. Community service at the very least to understand consequences for their actions.
Sounds like they need something constructive to occupy their time?
And maybe some therapy? Cause gees.

do you know any 14 year olds tougher than them that can lean on them?

This is the kind of situation that our society has decided not to act on. Parents are giving broad latitude with children. Even in cases of physical or sexual abuse, the child's life has to be in danger before a government agency will intervene. I wish you well, but have no suggestion of a solution.

File a restraining order. Get an attorney and sue the parents.
Or sell your house and move.
Your options are rather limited.

Have you caught them in the act? Perhaps some video would convince the police to act.

We have ASBOs and problem neighbour policies here. They work

We have reported these kids to the police without any solution to the problem. We finally have reported them to child services. We just heard that they were expelled from school and must attend a school for "challenged" children. This still requires them to live at home.