I'll third the people that haven't had any major problems in 20 years. Never had lice, never wormed & only lost a handful to unknown causes. Never have used chemicals or wormers either. Feed them well & like others said, give them space. I started keeping chickens because of an article in Organic Gardening that told me all I really needed to know. I then picked up a chicken keeping book (there weren't many around in 1993!) & got freaked out with them talking about confinement & all the diseases etc. I decided that book was not for me as a backyard chicken keeper. I had small children when I started & while we did tell them to wash their hands, none of us probably did all the time & we never got sick. Just give it a try & you'll do just fine.