as long as you feed them grain it wont hurt your plants. i used pig castings for years just make a compost pile of the goat shit and grasss trimmings,eggshells,coffeegrounds,or anything that will decay and let it breakdown in the pile before you use it even if you just mix the goat poop with potting soil it will ammend the soil but let it sit in the sun for a few weeks to breakdown and it will be less harsh than just putting it in.