Just started using the AC in my2015 and it smells like manure, bad. I bought the car in October 2015 and I know the car sat on the lot since November 2014.

try changing the cabin air filter...see owners manual for location of the filter....

As the car sat on a lot through a New Hampshire winter and summer, you could have a dead animal in the ductwork. Start poking around and sniffing to see if you can pinpoint an area of strong scent.