This is a quote from a Florida Extension Service article.
The chickens pick up the parasite eggs directly by ingesting contaminated feed, water, or litter or by eating snails, earthworms, or other insects (intermediate hosts) which can carry the eggs. Further down it mentions earthworms and grasshoppers as intermediate hosts for roundworms.
Just for the record, here's a link to the article. The recommendations look like they are more for commercial growers than for me so read them and apply to your situation. I'm personally not going to use insecticides to try to kill insects that might come into contact with chickens.
http://edis.ifas.ufl.edu/VM015
Unless you keep your chickens in solitary confinement, away from earthworms, insects, and wild birds, there is a great chance they have worms. The contaminated feed, water, and litter means that it has bird droppings in it, like when an infected bird perchs above a feeder or a wild bird leaves a deposit in the run. That thread Eggs4sale gave is great on treating them. Twice a year makes sense to me.
The chickens pick up the parasite eggs directly by ingesting contaminated feed, water, or litter or by eating snails, earthworms, or other insects (intermediate hosts) which can carry the eggs. Further down it mentions earthworms and grasshoppers as intermediate hosts for roundworms.
Just for the record, here's a link to the article. The recommendations look like they are more for commercial growers than for me so read them and apply to your situation. I'm personally not going to use insecticides to try to kill insects that might come into contact with chickens.
http://edis.ifas.ufl.edu/VM015
Unless you keep your chickens in solitary confinement, away from earthworms, insects, and wild birds, there is a great chance they have worms. The contaminated feed, water, and litter means that it has bird droppings in it, like when an infected bird perchs above a feeder or a wild bird leaves a deposit in the run. That thread Eggs4sale gave is great on treating them. Twice a year makes sense to me.