this article has excellent advise on not feeding large amts of earth worms to chicks
This would make the need to feed daily 2% of given feed in DE and worm the chickens
the DE goes thru the gut and knicks the soft shelled worms and they die of dehydration
But the need for chemicallyworming is to get into the blood stream and kill the worm larvea to get the other worms at least every three months
some of the thoughts are
Clinical signs of parasitism are unthriftyness, poor growth and feed conversion, decreased egg production, and even death in severe infections. Furthermore, parasites can make the flock less resistant to diseases and exacerbate existing disease conditions.
Of all the intestinal worms, large roundworms (Ascaridia galli) probably inflict the most damage. Young birds are affected more severely. A mild infection is often not noticed. Large numbers of worms, however, interfere with feed absorption causing poor growth and production. In severe infections there can be actual intestinal blockage by the worms, causing death. Affected birds are unthrifty and more susceptible to other diseases. Roundworms are passed from bird to bird by directly ingesting the parasite egg in fecal contaminated feed, water, or litter, or by eating grasshoppers or earthworms carrying the parasite.
Another worm commonly found in chickens is the cecal worm (Heterakis gallinarum). While it rarely causes problems in chickens, its chief economic importance lies in its role as a carrier of the organism Histomonas melegridis, which causes a deadly disease in turkeys known as blackhead. Earthworms ingest the cecal worm egg containing the histomonad organism from the chicken litter. When the earthworms are ingested by the turkeys, they become infected. The cecal worm egg containing the histomonad organism may also be directly ingested by turkeys. Thus, one should never house chickens and turkeys together or allow turkeys on range which chickens have previously occupied.
Other intestinal parasites that cause problems are the small roundworms (Capillaria sp.). These parasites infect the intestines causing hemorrhage and thickening of the intestinal walls, leading to poor feed absorption and poor growth. Small roundworms are passed directly from bird to bird by ingestion of the parasite eggs or by ingestion of earthworms, insects, and other vectors carrying the parasite. Tapeworms are also very common, but unlike other worms must be passed through an intermediate host, such as a snail, slug, earthworm, beetle or fly.
Also the deficiencies of Vitamins A and B complex when feeding earth worms
you can do much harm to chickens health and well being here
any questions email me
