Rat poisons are lethal and can be harmful to your pets; hence they must be used efficiently. Poisoning rats put your pets and kids at threat of getting in contact with the toxins. Trapping a mouse and letting them loose far away is a recommended option.
Another primary reason to not use rats poison is that the nest could be in a place unexplored by you, so when they die, it's hard to find the corpse. Not only this but the body of a rat produces an unbearable odour that will make the situation worse.
Therefore, it's best to leave the matter into the expert's hands.