I keep my chickens indoors so they hear me go about my business all the time. The rooster makes a "brrbrbrbrbrr!!!" sound after anyone sneezes, coughs, or pshaws or makes some other loud burst-of-air noise (i'll leave you to your imagination there...). It's sooo funny. He only does it if he can't see the source of the sound though. If you sneeze right in front of his face, he won't react. If you sneeze in another room, you can expect to get an angry sounding grggrbrbrrbrrrbrrggrrr!!! back. Anyway, best explanation I can sort of make up is, I remember in high school, our earth science teacher took us out to the fields for bird watching. He made 3 weird noises to "provoke" birds into making their calls - pshhh pshh pshhh, psss psss psss, and this loud loud kissy sound (basically all you do is put your index and middle fingers together, and kiss right in between the back of them... it's so shockingly loud). He said these sounded like distress calls and it made them vocalise to pass the alert to other birds around. So yeah... works every time. If you try to beatbox (but not in their field of vision), the rooster will contribute a very well-timed BRBRBRRR sound. Anyone have similar observations? Try it and tell me if you get any results.