OK, it's not the greatest system, but last night it worked. I'm still waiting for the coop to be finished, so we moved the brooder into a pen a few weeks ago. Since it was supposed to be very temporary it is jsut 5' chicken wire wrapped around some stakes with a tarp covering half of it. I sited it under the branches of some trees for hawk protection. And, as I am a light sleeper, under my bedroom window. Even better, one of the windows has the cats' cat seat on it and I'm sure to always leave that one open. Well, at 4:22 am my Maine Coon "kitten" (she 3 1/2, but still acts like a baby) bolts out of bed and starts jumping onto all the window sills growling and hissing her head off. My older DSH, nonchalant as ever, looks at her like she's nuts. I go over and look and it is one of our neighbor's not very nice cats (he scratched me once for no reason and used to beat up a stray I fed). So, on with the slippers and out the door to chase it away. Anyway, no chicken tragedy, thank goodness, though the girls weren't so happy being woken up at 4am when I did a head count. But at least I know my kittens on the job! Hopefully she hates racoons as much as other cats. Here's my brooder in its pen before we expanded it by plywooding in the entire bottom to make a larger indoor area with perches.