2018 Prius Prime HV Battery Smell

First of all let me say that I am trained for HV battery work from my time with Generous Motors.
So after visiting my brother in-law in rural Nevada my 2018 Prime developed a very bad odor of something dead. The smell was strongest from the battery cooler vents on either side of the back seat. I took the back of the car apart and found some evidence of a rodent animal waste but nothing concrete. I did some cleaning and put it back together. Another 2 weeks and the odor is getting worse and I can't stand it anymore, so here we are.
For those who have not really studied the cooling for the Prime L-Ion battery, air is drawn in from the passenger compartment, blown into vents inside the battery compartment, and then exits the battery compartment back into the passenger compartment. Mounted on top of each battery assembly is a duct that takes any off gasses from the battery outside. The duct exits the bottom of the car near the back bumper. The duct has no screen or anything to block small creatures from entering, and so here I am with a very dead and smelly mouse that got into the middle battery pack duct and could not turn around to get out as best as I can tell.
I will be cleaning and bleaching the duct in hopes to kill the smell. I will also be adding some kind of screen to keep out rodents, but not block the needed airflow.
For those of you who have to park outside, or might have rodents where you live you might look into putting something in to make sure you don't end up like me.
A little more clarification on the cooling path. The yellowish ducts on top of each row of cells direct any offgas from the cells outside the vehicle. The cooling air that is forced into the battery pack from the fans, does NOT exit the vehicle, but just exits the pack at the back and remains inside the car to recirculate. Any air that circulates into the battery pack is dependent on the temperature of the air inside the vehicle to warm or cool the pack.