@dadpad,
each cyst or worm is distinguisheable in a fecal count. It may be overkill but we have a herd of sheep and when you findcysts in the stool in the pasture, you canassume its all through the herd. AND its really the best way to determine the success your having for any wormer.
We dont do "range pasturing" so when we rotate pastures we can either be re infecting or keeping the stock worm free.
I hate having to check under the eyelids to see how bad the parasitic anemia is, thats really hard on sheep and cows. SO the fecal worm count is a good way.
The way I do it is once every two weeks or so, I go out and snag some doo doo in the pasture . I especially look for dumps that appear less "Thrifty". I bring em back and mix a sample and mix it with a flotation sugar solution. Then I centrifuge and do a count. All these are taken with weighed samples . I do a count with a reticle and I compare em to a U of Penn worm cyst and larvae cheat book.
We keep fairl;y good records of seasonal worm "blooms" and our med regimen. Its a bit of work but its better than unexpectedly losing a good breeding ewe or a top ram when they start developing the typical "bottle jaw" symptoms and then treatment is touchy and not always successful.