Struggling social media company Twitter Inc will see three more top officials depart, and it plans to add two new board members, a source familiar with the matter said on Sunday. In addition, Jason Toff, who heads Twitter’s video streaming service Vine, as well as business development leader Jana Messerschmidt, may also depart. Twitter plans to announce the departures on Monday, along with the recruitment of a new chief marketing officer, according to the source familiar with the matter.