worm castings is worm shit, not living worms. living worms won't hurt your plant only help it, but make sure there's not too many because they will attract other insects.
Worms are great for plants. They aerate the soil and leave behind fertilizer(castings). And chicken shit is high in nitrogen. Too high to use right out of the chicken. It will burn the fuck out of your plants. It needs to be composted first to mellow it out.