I currently have around 200 mice, sitting in one room...Here's what I do to help eliminate the odor...I add about 20-25 drops of grapefruit seed extract(not the concentrate, if using concentrate it's more like 6-8 drops) and 1 teaspoon vanilla to 1/2 gallon of water...It works wonders in controlling the odor, and it doesn,t taste too bad...Yes, I always taste the mice's water...
Try this and you'll be a believer in no time...
HTH,
P.S. GSE also works great for the snakes, since it helps reduce the ammonia smell and even kills some internal parasites that you don't want them to have anyway...