Comment to 'Change Homepage Feed from "feed" to "public"'
  •  Go to Studio--> Developer-->Pages-->System-->Homepage

    Click on Feed (Timeline) and set Inactive and Save.

    Click on Public Feed (Timeline) and set active and Save.

    You will also need to make sure that Create Post (Public) is set to Active as the Public Feed (Timeline) uses that post form so that users may post on the public timeline.

    May have to go to Dashboard and Clear All Cache after that, but try viewing your site first after a browser refresh.