If I type "next Blackburn Rovers manager odds" into Google, the top result is from Oddschecker. The preview underneath has Graham Alexander 4/1, Coleman 5/1, Hughes 6/1, Bilic 6/1, Savage 8/1.
When you click the link to go to the website, it doesn't display Rovers managerial odds, just the Man Utd, Palace Leicester etc. odds.