One of my hens was looking thin and then I saw a roundworm in droppings this week-ugh! Based on various posts on this site, I decided to worm my hens with Valbazen (albendazole). Afterwards, I had some serious second thoughts, which led me to do some additional investigation, which ultimately calmed my nerves. The recommendation to use Valbazen was a good one! Thanks to BYC! The article that calmed my nerves describes research done on broilers using 3 dose levels of albendazole (5 mg, 10 mg and 20 mg/kg body weight) and then measuring the effectiveness by doing necropsy analysis 7 days after treatment. Here is the link to the journal article: http://japr.fass.org/cgi/content/full/16/3/392#T1 Summary of study findings and how Ill manage my flock: 1. There was a high incidence of worms in this 1 year old flock, maintained on litter. Incidence: o Ascaridia galli (roundworms)73% adults; 80% larvae, o Heterakis gallinarum (cecal worms)100% adults; 73% larvae o Capillaria obsignata. (capillary or thread worms)100% adults; 100% larvae o Raillietina cesticillus (tapeworms)53% 2. There were no adverse effects of albendazole treatments on bird appearance, behavior, apparent appetite, and weight gain. 3. Good control was seen at 10 mg/kg for all worms except tapeworms, which required 20 mg/kg for control. 4. Through other medical websites, I found that albendazole is used to treat humans with worm infections. 5. Conclusions: o Since there is a very high incidence of worms in chickens raised on litter, I plan to worm my chickens 2 times per year, or more frequently if I observe worms or weight loss. o I will use 10-20 mg albendazole/kg body weight, which translates to: - 2 pound chicken ~0.1 ml Valbazen - 4 pound chicken ~0.25 ml Valbazen - 7 pound chicken ~0.5 ml Valbazen o Ill not eat the eggs for 2 weeks, although since albendazole is used in humans, this is probably not essential. I hope others find this useful.