Spike seems to get grumpy sometimes and bites like crazy not hard or anything. He is about 13 weeks old now. Do cockatiels teeth? I guess he is just tired and bites when he is grumpy gets sritched the wrong way or I offer him something he does not want, like corn

. Does anyone have any tips. Thanks for the help.
my Ollie does the same thing one minute he is sweet and looking for a head scritch the next minute he is attacking my hand...lol of course it doesn't hurt but i just tell him no and remove him from my hand for a mintue or two and then I let him come back
I found this info on the internet
No": Like other pets and children, the word "no" is key to owning a parrot. Early on, teach your bird a no-type word to associate with stopping an action. The necessity of this will probably first rear its head when your bird is in the "teething" stage. Of course birds do not have teeth, but they do go through a stage where they mouth play (usually with their owners) and they test how far you will let them go with biting, and how far it can get them. If they bite too hard say "no" in a stern, abrupt, firm voice and glare at them straight in the eye (some people choose to use the word "ouch" for this specific training exercise). Because you stop the playing and use a shocking voice, the bird will learn to associate "no" with the play session being taken away. In addition, the stern, loud voice is often shocking enough to get the bird to stop its activities. Teaching your parrot "no" will be important if he ever gets ahold of a dangerous object in play, or attempts to get himself into a dangerous situation when out of the cage.