Updated from 8:33 a.m. to include comments from Twitter and information on new departures.

NEW YORK (TheStreet) -- Twitter (TWTR) - Get Report is scheduled to report its second-quarter results on Tuesday afternoon, and while most analysts are waiting to hear an update on the company's CEO search, staff turmoil at Twitter may go much deeper than just the C-suite.

More than 450 employees -- 12% of the company's staff -- have left Twitter in the past year, according to The Financial Times. That number is likely conservative because The Financial Times gathered data from LinkedIn (LNKD) , and not all Twitter employees have LinkedIn accounts, but it certainly shows that there is some chaos at Twitter. Despite the departures, Twitter's total headcount has increased 18% over the last year, according to The Financial Times.  

When reached for comment on these numbers, a Twitter spokesperson responded: "Great teams want to work on something people use daily, and Twitter is such a product. This, together with the impact people can have on the world through Twitter, helps us attract the best employees."

The high turnover shouldn't come as much of a surprise given the amount of attention the company has been receiving both from analysts who are dissatisfied with the company's growth in users and revenue, and from commentators critical of Twitter's lack of diversity and "brogrammer" culture. Twitter's disappointing first-quarter results eventually led to Dick Costolo stepping down as CEO and Jack Dorsey coming in as interim CEO while the company continues to look for a permanent CEO.

Since April, shares of Twitter have dropped more than 34% amid concerns about slowing user growth.

On top of Costolo, Gabriel Stricker, Twitter's head of communications, left about two weeks ago; Chloe Sladden, vice president of media, left the company in August; Vivian Schiller, who was the head of news and journalism partnerships at Twitter, left in October, after just 10 months; and April Underwood, director of product, left in February.

Tuesday afternoon, two other notable Twitter employees added their name to the list--VP of Product Management Christian Oestlien left for YouTube and Product Director Todd Jackson left for DropBox.

Other notable employees who have left in the last year or so include Jim Payne, who was the chief executive of mobile ad serving company MoPub when it was acquired by Twitter; Rishi Garg, head of corporate development; early Twitter employee Jessica Verrilli; Cynthia Gaylor, who led corporate development; and Chief Operating Officer Ali Rowghani.

After Garg left Twitter in June, SunTrust analyst Bob Peck noted in a research note that the succession of departures "underscores a 'brain drain' risk for the company" and that Twitter should work fast to get a new CEO on board to stem the losses before they get any worse. "While some key talent may leave the company while it is in flux, it may also be difficult to hire new key talent without a permanent CEO being in place," he wrote.

The challenge of attracting and retaining talent in Silicon Valley is always difficult as some of the biggest tech companies and start-ups fight over a finite number of candidates in the area, but Twitter's reputation for chaotic transition surely won't help the company.

"They're in a war on talent, and they have to market their brand to get candidates interested," said Brin McCagg, co-founder and CEO of recruiting startup RecruitiFi.