In the first Omni rat/mouse war, I found the most effective and humane traps to be the (electrocuting) rat zappers. We bought one a long time ago, good for about 60 zaps, but it disappeared so far as I know. A bulk order of these, if affordable, would likely do wonders. 

A good thing to do aside from traps would be to plug all holes in Omni walls / floors / roof larger than a dime. Really, that small. This on the advice of the plumber who conducts daily skirmishes with rats in the course of his daily work. Rats also live in rat-caves under the foundation. Where the foundation has holes or is exposed, should be sealed up. 

Hunting for such orifices might be a good group task for the rat brigade. Spray foam insulation + wiremesh to plug, or drywall & caulk.

Note that rats get up to the roof through the cypress trees, but we shouldn't top them, or they get permanently out of wack.

Vaya con dios, 
Dk

On Thursday, February 4, 2016, robb <sf99er@gmail.com> wrote:
i, hereby, publicly declare war on the rats at the omni. please deploy and maintain live traps if you object to the campaign as snap traps will be the weapon of choice. this war has no leader or general but strategy sessions will be held at 8:00pm every monday. please attend or contribute at https://pad.riseup.net/p/rodent-war-plan
thank you
~r