DE supposedly works on the premise that the particles are of such hard and sharp design that they excoriate the worm's skin enough to cause the gastric juices to penetrate and kill the parasite. I've never used it on my chickens or animals.
In the wild, saw grass works in much the same way for many animals, which is why you will occasionally see both your dog and your cat chew on blades of saw grass. This is a natural way to rid of existing worm loads. The grass is indigestible for these animals and passes into the intestines pretty much intact and effective for it's purpose.
Here's an interesting article that everyone with livestock needs to read if they are concerned about worm loads.....
http://nofavt.org/assets/pdf/Parasites.pdf
Quote:
Many producers have claimed that they have had good results with DE, but their management is usually
very good. They may be giving credit to the DE when they should be giving it to themselves. Although I
have nothing to back me up, I've often wondered if it isn't the minerals in the DE that provide the benefit.
Worm egg count also naturally falls at the end of summer and the beginning of fall. People who are doing
fecal egg counts (FEC) may be thinking the DE is lowering the egg counts, instead of realizing that it is
the natural cycle. I haven't talked to any producer who uses DE without significantly changing and then
watching their management.
Using DE is not just a simple substitute for a chemical dewormer. This is another problem with the
scientific research that has been done on DE.
Researchers have simply substituted DE for their
conventional wormer and done everything else exactly the same. This is component research, whereas to
really prove that DE has an effect, systems research needs to be done, using the same or similar
management techniques that producers use. This type of research is much more difficult to do. If you still
want to use DE, one dosage that I've seen used is ten to twenty pounds per ton of mineral supplement.
Every animal must be fed a dose every day to be effective
Important to note this paragraph...this is something I've been preaching for some time about existing worm loads in healthy animals and proper management to produce animals that thrive with little intervention like deworming:
While it is usually neither possible nor advisable to completely eliminate internal parasites in sheep or
other livestock, reduction of parasite load can be achieved. Many people have found, and research has
shown, that
adult animals rarely need to be wormed. Most animals develop immunity against internal
parasites, though not to the level that is developed against viruses and bacteria. This immunity keeps the
parasites from reproducing but rarely kills them. An example of an effective parasite control program can
be found in Tennessee. Dennis Onks, superintendent of the Highland Rim Experiment Station in
Springfield, Tennessee, has not wormed the adult cattle on the farm in eight years. They are wormed at
weaning, around 7 months of age, and then not again. They have never shown any signs of internal
parasites and their condition is excellent.
These animals are on a high plane of nutrition, have a low stress
level, and are strictly culled on production.
All these things work together to produce an animal that
shows no signs of internal parasites.
....
animals that continuously graze a pasture eat the grass into the ground, while contaminating
the soil with so many parasites that nothing outside of regular deworming with chemicals will control
them. By using controlled grazing methods that allow pastures to rest and soil life to function well,
contamination can be reduced. This reduction occurs because soil organisms, including earthworms, dung
beetles, and nematophagous fungi will destroy or keep a lot of the parasite eggs and larvae from
developing.
Keeping the grass in a more vegetative stage, and tall enough to provide the animal with
adequate forage, will provide better nutrition to keep the animal healthier, strengthening the immune
system to prevent the adult worms from producing eggs. Parasites do not cause as much harm to a
healthy, well nourished animal. The parasites that are present will not deplete the host as much as in an
animal that is malnourished. Parasite loads affecting wildlife generally do not cause the death of the host,
because the parasites need the host to survive. The same principle applies to livestock.