I suggest you check your by-laws, available from HOA {homeowners' assoc.}, and request permission from landlord if you could erect said fence yourself.

 Landlords do not have any obligation, under any housing acts and will only provide fencing if it is written into your tenancy agreement (which is unlikely). Check that but if not, then they won't do. Fencing is costly for Housing Associations and is often rationed carefully. Having said that if you complain enough about the kids, they might get sick and agree to do. Good luck xx

 Yes of course its your right .You must ask him and tell the problem you are facing for long .Most probably he will agree to do act in your favor.

 You aren't going to get much of a response out of this, it's probably best that you go and talk to the landlord/tenant board, even with the housing you are in, you have rights too. If you have complained several times before, then it means that they have no intention of trying to resolve the problem. Hope this helps, good luck to you.