Diatomateous Earth is good for all types of parasites. If you can't find Piperzine in the feed store, and you're in a pinch, check out the dog and cat section at the food store or pet shop. You can find puppy and kitten wormer, which is piperzine. Follow the directions based on weight. Ivermectin is effective against a large variety of worms and works also against mites .
Some people use it for chickens.
It is expensive. Crush 2 tablets and soak in some water overnight, then make 1 gallon of water and provide as the sole source of water for 2 days. If this is the first time you are worming the flock, repeat in 12 days. Some people worm once a month. Some people use garlic and believe it's a wormer - apparently garlic is a mild form of natural antibiotic and acts to a small degree in limiting the growth of nutrient robbing bacteria from the gastrointestinal tract.