TLDR: Is >1 year too old to litter train?My boys are 1 year 4 months old and are fixed. I adopted them at 4 mos and I tried to litter train them right away, but had some difficulty because one of them (not naming any names...Dewey) is a socially inept roommate and would pee and poop anywhere he wanted - in the bed, the food dish, etc. The others are clean little ratties and designated a bathroom corner away from their main living space even before litter training. The combo of the litter resistant rat and my long work days not allowing me to place every dropping in the litter caused me to give up after 3-4 weeks.Since then, I've cut the platic mat over their bottom floor so that the corner they tend to poop in is just wire, and the poop falls into the underlying tray. This has worked great, it seems more sanitary to me because they don't walk through or touch it. They still pee everywhere, though. The hammocks have to be washed every 2 days, and I can't use fabric covers because they get too stinky. I'm wondering if litter training can work for both pee and poop, and if they are too old to be trained at this point?