Ed...what tubs are you going with? I have the same issue the rats keep eating holes in the tubs (I have no idea how they manage to eat holes in the solid bottom - when there is no edge...but I keep seeing heads popping out)
I am going to be building a whole new rat rack setup and trying to decide what tubs to use...I am thinking I will need to push the breeder rat numbers up to 100-125 range so planning it out now.
Thanks