I bought four day-old sexed pullet chicks from MPC. they are now 6 wks old. since the first week, someone in the brooder was "trilling". couldn't catch them in action, so don't know which chick was doing it. now, in the big Catawba Coop, every night when they march upstairs there is much peeping and one, lone, trill (baby monitor). does this mean i have a roo in the flock? they free-range every evening when i get home from work and i don't hear it then. tell me trilling is a sign of contentment....please....?