I found chili powder only medium-effective in deterring catsd and squirrels. Even light rain reduced its effectivness.
So I spread chicken wire over freshly-turned soil or recently-planted bulbs. That worked, I just had to remove it before sprouts got too big.
Maybe after fresh manure has been int he ground a while, the dogs won't like it as much. If so, and you don;t mind wheelbarrowing it around twice, you might be able to make a big pile and surround it with wire until it aged enough to lose its allure.
I'd do anything to get free manure!
