I had the feeding trough out and full of hay but my animals were still complaining of needing to be fed. They hadn't eaten at all since I had bought them (maybe 3 or 4 game days). I had the trough at an angle in the corner of the barn. Basically it was in the corner but so that it formed a triangle with the barn walls? I was trying to figure out if they could access it or not. As soon as I moved it to be parallel with the barn wall, they all ran up to it to eat.
This should be game mechanic probably, not user interface. My bad
Sometimes the eating/drinking is finnicky and moving the troughs seems to help