First of all, I've never heard of someone keeping a pet pigeon in the house. Pigeons belong in coops in the backyard. Birds are basically incontinent, and poop wherever they happen to be when the need arises. Some birds will poop as often as every 15 minutes, so I can imagine the mess when a bird is allowed free roam of a house where people live. I used to have several pet birds and they were never allowed to remain outside their cages for long and would always return to those cages when they needed to go.
Secondly, as far as vicious pets are concerned, yes, they happen sometimes. I think many times the pet in question just likes to play rough. My cat is like that. She plays using all of her weapons, including teeth and claws and even vocalizes while playing. (hissing, growling) She has incredibly fast reflexes and can swing her paw away from me and in the next second swat me on the hand with it faster than I can blink. I can tell by her facial expressions, and by her tail movements whether she's actually angry or not.
Also, some pets like to try to be dominant. My cat is also an example of this. She has an alpha cat personality, and does think she is head and shoulders above the humans in her 'care'. She absolutely believes that she deserves the prime spot on the bed at night and anyone who thinks otherwise gets a hard bite on the offending limb that stretches into 'her' space. I've been known to simply shove her to one side, which means she has to get up and leave the room as that sort of thing can't be tolerated.
I've never had a pet who was vicious just to be vicious. There was always a reason for it, such as previous abuse, or sensory overload of some kind. And of course, there is the 'Queen of the Universe' that I currently live with. She has some interesting catitude.
