I had a stray show up last summer, he's a real good hunter. All the hoards of lizards in my yard were gone in a month . He walks up to the chickens and tries to rub lovingly on them with his head and neck.
I had a stray tabby show up and do this. That rubbing isn't 'love' though -- it's cat spit. They have glands at the corners of their mouths and they're marking stuff by rubbing their scent on it.
So, what, he's trying to mark the *chickens* ?? He never tried to hurt them though, he just followed them around -- the worst he did was try to steal an egg. After which I finally gave up and started feeding him, so now he lives here. (The chickens wanted nothing to do with him so now he's attached himself to the dog...)
101112_4259 by wsmoak, on Flickr