Our dogs have been getting rattlesnake shots for several years now. We don't normally see them where we live, but we do travel to places where they are around. I also plan to take Ollie the rescue dog to snake aversion class in the spring. Those Mojave Green rattlesnakes are VERY BAD NEWS.
As far as needing grass to poop. Our very first Lab, Lucky, would only poop on top of a bush. Not terribly easy to clean up after! Fortunately, we lived in the country when we had him, and he found that a stray alfalfa plant did just fine. We didn't have enough of it to harvest, but there were plenty to use as outhouses.