Something that helped me feed the chicks baby food without all the big birds eating it up, was to stack about 3 or 4 pallets and dump the baby starter crumbles on the ground in the center of the pallets. Just stack them so you have a clear shot at the ground under them and dump the baby food in. The pallets also act as a Biddy Fortress that they can escape any big birds if needed so they get to eat in peace.
I got the idea from an old 1940s wooden brooder/heater a neighbor had. Take one sheet of plywood and cut it into 2 - 48" square pieces. Then cut one of the halves into 12x48" pieces for the sides. Cut 3 little 3x4" door openings into each of the sides for ventilation and so the babies can get in and out. In the 48"square top, cut 3 - 6" holes, one in the center, then one on each side between the center hole and the outside walls. You put heat lamps over these outside holes and use the center hole to pour feed in. If you have it in a pen with adult birds you may have to make a cover for the feed hole. As the babies get bigger and need less heat, you can put bricks/blocks under the box to jack it up. Cheap, simple and effective.