Hello and welcome. Thank you for requesting me. I apologize for the delay. I was not online at the time you posted your question, and am not sure why I was being shown as online. I just logged on and saw your question. I'm sorry to hear of Mitch's problem.
Your vet should be able to trim the bottom beak. While you're there, you might want to ask a vet about the underlying cause for the overgrown beak. If a cockatiel has a cuttlebone, mineral block, and toys to chew on, its beak shouldn't get too long. The exception is if there is a health problem, such as liver or kidney disease, or if the bird is being fed an improper diet. Sometimes, an inherited defect causes the problem, and in that situation, all you can do is have the vet trim the beak. By scrolling down on the following page, you can read more about overgrown beaks:
Diet is the single most important factor in keeping our birds healthy. Most people still feed a diet consisting mostly of seeds, but recent research has shown that an all-seed diet is not good for cockatiels. Pellets, supplemented with various fresh and healthy “people foods,” along with a few seeds make up a healthier diet. Birds that are fed mostly seeds tend to develop fatty liver disease, tumors, and other health conditions. However, if Mitch used to eating mostly seeds, you’ll have to convert him to pellets gradually. The following two sites are where you can get reliable information on feeding and care. The second one has a section on converting from seeds to pellets.
You may already feed Mitch a pelleted diet, but I wanted to provide this information just in case. If you have more questions, let me know in a REPLY. I hope your vet will be able to quickly see Mitch and get his beak trimmed.
My goal is to provide you with excellent service – if you feel you have gotten anything less, please reply back, I am happy to address follow-up questions. Please remember to rate my service only after you have all the information you need. Thank you!