When mine first started doing it, it was always when I got home from work, but he wasn't talking, he was just screaming and wanted to bite. I took it as punishment for leaving him alone all day although he had plenty to amuse himeself with, Pretty soon after his droppings became very wet and mostly transparent. He would just sit in his corner on top of his cage (he was only ever inside to sleep). His eating and drinking slowed and then he started just walking over to me and staring at me. It happened so fast, but did it. It took 10 minutes for the vet to diagnose him with giardia. And he was put down. There is no worse feeling than seeing this little yellow head go limp and thinking, maybe a week sooner, if I had been more alert, he could have been saved. And didn't have a dirty cage, so it comes from anywhere. I held him all the way home to bury him, but you can't make their little eyes close, he was paying attention, I wasn't.