I've never heard of chickens being a problem. cleaning out a cat box, yes, but chickens, no!! you could always wear one of those white paper masks if you're cleaning the nesting area or picking up poop. maybe your friends are concerned about you breathing in something from the poop, like that disease you can catch from breathing in rodent droppings (hantha virus?) it sounds like you take good care of them. the lack of info on the net makes me think its not a problem also. pregnant woman have tended chickens for hundreds of years, so i'm sure if there was a problem it would be known (like the cat litter thing). good luck and congrats on the baby!!