I've seen this a few times now ... J is the worst .... he'll think nothing of starving himself for up to three months at least once a year. Suzy is currently on a fast (her first time) currently on her second month. Panama has also had one or two two month fasts in my care. It worries me every time .... but as soon as I think it has been too long they seem to suddenly switch on again .... I'm sure it's their way of deliberately freaking the pink monkey out