I had a serious rat problem in the barn last year.  I needed to put out poison, but with my precious puppy darlings, I had to be very VERY careful.  I have 2 7 x 12 kennels that I use as breeder pens, to I took all the chickies out of one of them.  I then put a small puppy cage inside the kennel, and put the Just One Bit in the cage, so it was double safe from the puppies.  Those rats when thru a LOT of bait.  It was pretty interesting (as interesting as killing rats can be).  The first dead rats I would find were the full grown ones, then half grown ones, then smaller ones, then bitty ones.  Then no more.  Took about 10 days of solid baiting, but I bet I found over 50 dead ones, which doesnt even begin to mention the ones I didnt find.  I havent seen any evidence of any this year, but if I do, Ill go right to Just One Bite.
Good stuff.