I usually worm my chickens with Wazine but I was told I should worm also use ivermectrin injectible after the wazine. I can only find it available for cattle and im confused about the dosage. Where should I buy it from and should I give it orally or on the skin because I see it can be done both ways. Please help me im confused and I don't want to give my Silkies the wrong dosage.