We have used four boxes of poison for not quite 4 days now. 2 'feeding' locations have been used out of the 4. We know of 3 rats for sure, as we saw them, and maybe more. The 3 previous nights they ate ALOT and we have had to replenish their supply at one location, with a box that they never touched from another location. Last night was the 1st night they did not eat a thing and we haven't seen any of them this morning. Usually we see them going into hiding by this time. So now we know it probably worked and now we are waiting for the smell ... yikes! This is all we could do about these pests as nothing else worked. (plug in electromagnetic devices don't work usually and traps are too messy and might not kill them and they will suffer longer.