not unless they are VERY VERY sick
Cockatiels do not need anything to have a mate. Just put him/her in the cage with your cockatiel, however, if you want them to mate, they will not mate if you do not have a nesting box. In order to breed cockatiels, you will need a nesting box.
You need to take them to the vets.
you dont need to take a medication if you have took yout seanson of shots
You have to take it in and have blood drawn from it, then wait for the results from the lab to tell you.
because in need to cheak if it is ok and for its shots
yes because you have to.
To sell cockatiels, you need to breed them first. If you have a permit for breeding, you can. If you have a bunch that you didn't breed, than you might be able to, I'm not sure.
Yes, cockatiels can get parasites.
they need all of the same shots as othe dogs.
Bunnies don't need shots
Whats your point? Define shots; shots of what?
Cockatiels are a type of cockatoo.