In my own humble way I will attempt to answer this "what does broody mean?" question. The term broody applies when a hen undergoes a hormonal change that tells her body she must sit on a nest of eggs until something hatches out of the eggs. These hormonal changes seem to be first exhibited by a crafty hen trying to secret away her eggs each day to gather a clutch. This is followed by crankiness (sort of like PMS to us women), accompanied by growling, snapping, pecking and a general unwillingness to move their butts off of the nest for ANY reason. I don't have a roo with my girls, but that doesn't stop them trying to go broody on me. As all 13 of them use the same nest box, it is an old wooden orange crate, this makes for some all out fights in there. I've had two broody hens monipolizing the nest box and found a third hen laying an egg on one of their backs pretty as you please. The hen will also, when really getting down to being broody, pull out their chest feathers so as to make sure they get good warm skin contact with the eggs. They don't get off the nest but once a day to take care of their necessities and then wriggle back down over them eggs. Now, infertile eggs of course won't hatch and unless you break up a broody (keep braving those snapping beaks to remove the eggs daily and throw her off the nest several times a day works for me) a hen will otherwise set until she dies. If the eggs are fertile they rule how long a hen remains broody by hatching out the chicks.