I have used pumpkin seeds to deworm my chickens but I can't find just plain pumpkin seeds in bulk. I needed them this winter when one of the hens I had recently bought presented me with a steamy splat of poo that made me do a double take.
She was quite obviously wormy. I couldn't find pumpkin seeds so I had to make do with a squirrel mix of feed from Tractor Supply that had a good proportion of pumpkin seeds in it along with sunflower seeds and corn. We ground up the squirrel mix in a food grinder and fed it in place of their morning scratch treat for three days. They loved it and it seems to have done the trick, I haven't seen any more worms. Can you buy just plain pumpkin seeds in bulk anywhere?
