I have some ducklings that are only a few days old(runners). I have a tote that is only about 2 inches high and is 12 x 9. I brought them outside and they loved "swimming" in their box. I was going to put it in the brooder but wasnt' sure if it was a bad idea? I can put the lid on it too and just open certain times of the day or leave it available all the time? what would be best? they can hop right in and out no problem if that matters...