This is one ugly disease! I have no medical or veternary training but I believe it is very important to share what we have learned about Bordetella Avium.
If you ever have a baby cockatiel who developes "locked-beak" have your birds tested immediately. You may even have to sacrifice several breeders in order to determine the exact cause. There are other bacteria and viruses that can produce the same this same "locked-beak" syndrome in cockatiels. This is the reason for testing your birds.
Bordetella avium must be cultured in a laboratory because it needs a specific environment inwhich to grow. I have not found a home test as of yet.
The symptoms I have seen in baby cockatiels are:
Babies which contract the B. Avium bacteria and develop the "locked-beak" should be put down. They will not survive and will suffer throughout the course of the disease until, mercifully, death occurs. Personally, I do not see any other alternative. I cannot bare to see and hear them suffering so.
There is good news though! This disease is curable in the breeders who are carrying the disease and passing it on to the offspring. PLEASE, DESPITE WHAT YOU MAY HAVE HEARD, DON'T DESTROY YOUR FLOCK. MOST OF THEM CAN BE CURED! If you have the cultures grown by qualified techs and receive a positive result, your veternarian can prescribe the proper medical attention to administer to your flock.
For more information regarding Bordetella Avium, please click here.