Comparing the competitive nature of roosters and hens
The hypothesis holds true: the roosters reached the feeding tray sooner than the hens.
The domestication of chickens first occurred in India. Persians followed suit, and so did the rest of the world. Chickens are reared for their meat and eggs. Chicken meat is cheaper than other meats. Hence, it is consumed more than any other kind of meat..
Use ducks or turkeys instead of chickens.
The experiment can also be repeated to compare chickens of different ages.
Chicken - http://en.wikipedia.org/wiki/Chicken
Rooster - http://en.wikipedia.org/wiki/Rooster
Chicken behavior - http://www.gallosuisse.ch/html/index.php?id=13&L=1
Adult supervision is required when handling live fowl.