I had put some rodent killer,thoughtlessly inside the house and somehow it seems it has worked ,but unfortunately it seems that the rodent has died somewhere underneath the floorboards and the smell of it is becoming unbearable.The smell comes from underneath two large rooms and removing the floorboards are next to impossible. Any suggestions please.
Thanks

That has happened to me more than once. The good news is that the odor will go away on its own over a weeks time. The little guys don't have much meat on them and once the ounce or two of flesh has decomped you won't smell it any more.