Snakes might bother very young chickens (just hatched) but usually won't go for a grown chook, even if we're talking ginormous carpet pythons. Eggs are much easier to get hold of as they don't run away - or peck! So you might lose the occasional egg to Joe Blake, but to me that's a small price to pay for keeping the mice and rats under control (you very rarely get rodents if there's a snake in residence).