A few years ago I volunteered for an organization that does community outreach for the youth in the area.
The organization does great work, but sometimes they fall behind on certain tasks, for example, updating their careers page to remove old and already filled job positions.
On June 12th I found a job posting I would be perfect for, and the closing date was June 21st. I followed all the instructions, and sent in my application. I didn't hear anything back, so 1 week later (June 19th), I followed up with an e-mail. The manager replied that all the potential candidates were chosen and contacted, and the position was already filled.
I'm currently job searching, so I'll come across several job postings with closing dates, is it unprofessional to ask if a job opening has been filled before the closing date?
I found this question, but it's asking about acquiring the closing date.