The Silo allows you to cut and store grass for feed and takes Robin two days to construct. It can store up to 
Hay (240)
Build Cost:
Gold (100g)
Stone (100)
Clay (10)
Copper Bar (5)
Use[]
Once built, the silo will automatically store hay. Using the scythe on grass on your property will convert the grass into hay and put it in the silo.
Click on the front of the silo to see the current storage.
Each animal building has a dispenser which will automatically pull the exact amount of hay you need to feed the animals in that building per day. The hay will still need to be placed into the proper feeding receptacles each day or if you have built that building to max level, an automatic feeder will do it automatically each morning
You can put hay back into a silo by putting it through the dispenser.