I have several of the 33 gallon, 44 gallon and large tubs from Rubbermaid or Sterlite etc.. I've seen people using them for their rats but don't the rats chew through the plastic sides? Since they have corners on the inside? Because I'm breeding rats right now and am looking for cheaper enclosures for them than the aquariums I presently have them in... So anyway, basically my question is.. how good are these to use after modifications for air flow?