i have never wormed my flock and the one time i had a sick bird taken to the vet the fecal tests were clean
in the fall the birds get the rotten pumpkin and squash. i cut them in half with a shoval and the seeds have a natural worming agent in them
i figure all my birds are clean right now because i gave them a few lugs of cherries every few days (when they eat all the previous cherries)
birds get the runs just like humans from too many cherries, course i wasn't expecting the black poo.... but pretty sure they are spoiled birds and have clean guts now.
this is probably the only flock given cherries to their hearts content.