That's just another 555 monostable circuit, which we've discussed already. It's not reliable for long on-times, which is why people have recommended the 4060.You can do that with this circuit here. Once power is applied to the circuit, the load comes on for a set duration then turns back off, even though power is still applied to the 555 circuit. If they leave the light on, then when you return to the barn, you simply flip the switch down then up to reset the circuit. Output will be relay contacts. You can adjust the duration by raising the cap value from pin 2 to ground. Go high as possible for more minutes, or increase the resistor values.
Circuit here:
https://www.youtube.com/watch?v=q1Gj_mkMcI0