Unlocking the feeder scene is not one of the prerequisites. You will need to have played all the optional scenes, and you can't have made more than 1 bad decision that contributes to getting the bad ending.
That includes all of these scenes: WGGTS001, WGGTS002, WGGTS003, WGGTS004, WGGTS005, WGBE001, WGBE002, WGBE003, WGBE004A, WGBE004B, WGBE005, WGAE001, WGFMG001, WGFMG002, WGFMG003, WGFMG004A, WGFMG004B, WGFMG005, FMGWG001, WG001M, WG002M, WG003M, WG004M, WG005M, WG009, WG011, WG013, WG014, WG017, WG018, WG021, WG023, WG032, WG058, WG065, WG083. This list may get longer as more optional scenes get added to the route.
The route guide explains how to get the bad ending so you would just not want to make those decisions on the route. https://www.deviantart.com/the-murp/art/Alice-Route-Guide-Growth-Academy-1236746..