A little back story.....I bought 2 female ducks at a swap meet in October of 2018. I have a regular avian vet and gave them a poop sample. These poor ducklings had every thing under the sun in their poop. They were quantined for over 40 days before they were allowed to be with my flock. Test after test was done along with many rounds of antibiotics to kill all the parasites. Manly found Coccidiosis, round worm, yeast infection and giardia. They have been treated and tested and given the ok by my vet to be introduced to my flock. They are thriving well and recently retested their poop, all healthy which is amazingly awesome! So my question is, in the area that the sick ducklings were housed for 40 days, expelling all those bad parasites How long will it stay contaminated? I live in Michigan and my vet said our winters are not cold enough to kill every thing...Mainly the giardiasis. This area use to be my garden area and I want to start gardening agin for my ducks. I have not let any of the ducks into this area since these ducklings were introduced into my flock. And it’s a big area that I would love to allow these ducks to come and go as they wish....but is this possible? Any insight on this would be greatly appreciated!