Me: yeah.
Sami: No! Where would they get hay!
Me: People feed it to them.
Sami: What if there are no people?!
Me: Then they eat grass.
Sami: What if it just snowed?
Me: then they dig down for the grass.
Sami: There's ten feet of snow.
Me: Then they eat tree bark.
Sami: But there's no trees.
Me: Then your deer starves to death, and also it suffocates because it's under ten feet of snow.
Sami: but it's a MAGICAL deer and it saw that ten feet of snow was falling all at once, so it jumped up thirty feet, and then it gently floated down and got it's feet a little stuck in the snow. But it got it's feet out.
Me: The deer is still going to starve to death.
Sami: Then the sun comes out, and it starts raining hay, so the deer eats the hay, but it chokes to death.
And that's why deer don't eat hay.