If you haven’t been seeing many deer this season, maybe it’s because you closed you pool too soon.
From the Baltimore Sun:
They didn't jump in.

They didn't fall in.

They didn't push each other in.

[Homeowner] Bob Olwine saw them walk down the steps and descend into four feet of water.

"They probably just figured it was a small pond and they could swim across," says Brian Eyler, a deer biologist with the Maryland Department of Natural Resources. "I've heard of deer getting stuck in pools before, but don't know anyone who actually saw them walk in."