This seems to be a subject of some controversy -
specifically, is it alright, and does it do any good to ask for feedback after an audition.
The answer is - it depends. Some companies are very up front about saying - we don't give feedback - don't ask. Others are more open to it. I do give feedback when asked (the reason this comes to mind is that I am in the process of doing it right now after our recent auditions). I like doing it because I remember when I was auditioning, and how much I would like to have heard how I did. By the way, I am talking about when you are unmanaged singer, and have to go after this information on your own.
Having said that I do, I also understand completely those companies that do not. It can be an overwhelming job to give feedback to every singer that asks, and so a blanket no eliminates any inequality in the process.
I suppose the best advice I can give is: If you are not sure whether the company in question gives feedback, ask: The worst that can happen is that you will be told no. In a best case scenario, you may receive some information that will help you continue to grow as a successful artist.