46 different sounds apparently. Some are the same noise made at a different volume to signify the degree or level of whatever. We bought a CD called 'talking to chickens' about 4 years ago and have been listening intently to our chickens since then. Different breeds speak different languages but are universally understood, presumably because the call is supported with body language as well -or maybe they are far brighter in that respect than we give them credit for. Like their eyesight is twice as acute as ours for both size of object and speed of movement, so they can see tiny fast moving things that we can't. And of course they can process two images entirely separately, which we can't do either. They also show a range of emotions which, if you don't know your chickens well, you wouldn't normally notice.
Funny thing last night. We arrived back late and tired after 6 hours driving and Rosie raised her voice to me, unusually I add. Bottom immediately started the alarm call!