I've recently been thinking about taking in another rat, I have 3 at the moment and I was wondering if my cage was big enough for 4 or if i would have to extend it? It's been extended before and you can see its really a bit of a diy job (it is all secure & sturdy), cages get quite expensive but I think it turned out quite nicely! Also, ignore the grey plate at the front, I didnt have enough bars! If I end up extending it I'll definitely swap it out after buying new bar plates.