Chickens can have watery or runny droppings occasionally, especially in hot weather when they drink more water. Some vets will let you bring in some droppings for a fecal float, if you call first, or if you happen to bring in another pet for exam or shots. If worms were suspected or if you want to treat occasionally to prevent a worm load, I would buy a proven product that works, such as Valbazen (albendazole) or SafeGuard liquid goat wormer/panacur horse paste. You will find those online or in most feed stores. Valbazen dosage is 1/2 ml orally for a 5-6 pound chicken and repeat it in 10 days. SafeGuard/Panacur dosage is 1/4 ml per pound given orally for 5 days. Levamisole (Prohibit) is an older drug, and can be put into the water. It is found online.