My breeding dens were busy with high-hour fails, so I pulled dark animals out of storage that were 8-hour hatch times. I put them in the nest before bed, and they were ready to hatch in the morning. They were both Wair Wolf eggs, which I saw in its adult form in a battle the other day and thought was really pretty, so I was motivated to bring them out of storage and into my forests.
So, sometimes you have an animal in storage that you can hatch that is either a duplicate or something you've just been waiting for a reason to hatch that you can use to fulfill an event requirement. Always good to double-check your storage!