I think Mandy was on the right track with her phenotype comments. The one thing Sadie has going for her is that she's extremely efficient in the heat. Lacys in general, at least the smaller ones bred from Hill Country stock, seem to handle the heat very well. Still, she usually outlasts the other dogs, which is partially due to her endless energy but also thanks to her perfect cooling system.
- Long, lean build. When she was a pup, everyone thought she was a Whippet mix. Her rib cage has filled out a bit, but she still has the legs and muscles.
- Slick, flat coat. She doesn't have the short hair of a greyhound, it is much longer than that, but it lays very smooth and is relatively thin. There is no dense undercoat.
- The biggest tongue I've ever seen. And as soon as it gets just a little bit hot, she has it hanging all the way out her mouth.
- A desire to jump in every single puddle she sees. If there is water around, she runs in and gets her feet wet, and she'll often lay in it really quickly to wet her belly too.
Put all that together and she does the 25 mile hunts Monteria is talking about with no problem. I've seen her almost hyper at the end. And yes, she does have a blue coat, but I don't think that would matter when hunting at night.