Thanks for reaching out with this beekeeping question. I'm sorry to hear you are finding dead bees in your new nucs.

I recommend taking some photos or videos to document what you are seeing. I also suggest reaching out to your nuc supplier. Some nuc suppliers make up nucs from their colonies in Michigan, and others import nucs from out of state. It's possible that your supplier has become aware of an issue with transporting the nucs or the colonies they came from.

It's normal to find dead bees in and close to a hive. Colonies have thousands of bees, and a lot of dead bees may be due to natural attrition. I wouldn't expect to find hundreds of dead bees outside of the entrance after installing a nuc. (Some bees in the colony do undertaking work of removing dead bee bodies from the hive, which is why we often find dead bees in front of the hive.)

It's also possible that the bees became stressed when you transported or installed them. My first suspicions would be that the nucs got too hot or too cold. For example, nucs can be overheated, especially if there are many bees in a nuc box in a warm vehicle. Feel free to reach out if you have additional information or context you want to share.