You'll be able to see gapes if you cut the chickens windpipe open. One dosing of any wormer against gapes is useless, might as well cull the birds.I didn't know that chickens require a higher dosage than goats. What I have been doing is adding the safeguard for goats to their water for 3 days, waiting 10 days and repeating. This isn't for treatment of problems, I just worm them this way 2 x a year hoping to prevent problems. If the chicken has gape worms, you will be able to see them if you look. I don't think giving safeguard in any form for just one day would be effective. Am I wrong?