A full silo and hungry animals: follow the hay
Trace one portion from silo to hopper to feeding bench. A full silo tells you that hay exists on the farm; it does not tell you whether an animal had access to it yesterday.
Check yesterday’s meal
Enter the coop or barn and inspect the long feeding bench. In a basic or Big building, interact with the hay hopper, select the hay in your inventory and place it in empty bench spaces. Set out one portion for each animal that needs an indoor meal. Putting hay in a chest or leaving it selected in your toolbar does not feed anything. After a dry day of outdoor grazing, unused hay can still be on the bench.
Identify the actual building upgrade
The Big Coop adds an incubator; only the Deluxe Coop adds the automatic feeder. The same Deluxe distinction applies to barn feeding. If you can hatch an egg but still have to put hay down by hand, the building can be working exactly as designed. A Deluxe feeder takes hay from your farm silos when the bench needs filling. It does not create hay when they are empty, and moving a silo closer will not make a Big Coop automatic.
Budget a winter in portions
Check the stored total at a silo, then multiply the number of animals that will need hay each day by the number of days remaining. Eight animals for 28 indoor days need 224 portions, which fits a single 240-unit silo. Nine need 252: twelve more than one full silo. Keep overflow hay available or buy it from Marnie before a shortage. When animals look thin, fix food access first; a heater affects winter comfort but cannot replace a missed meal.