So I rescued these three bearded dragons last month who are almost 2 years old and spear to be sisters, although the guy said two went into hibernation and one didn't so she is bigger , and at first she would Bob and the other two would wave their hands and I didn't think anything of it because they weren't being physically aggressive but lately I've seen them biting the back of eachothers necks (even the little ones are doing it) and their beards get pitch black and they don't let go for anything I have to pretty much open their jaws. I can't afford two extra set ups for the others if I need to so I'd have to get rid of them which I don't want to do as I rescued them from family , but I will do it if I need to. I just got them a new tank aswell as the other one was really small , could they just be getting stressed out over that?