All big now and weaned! More or less.
This warmy right here
saved the day when they were little and sick and couldn't regulate their body temp. We actually borrowed it from the rescue group and had to give it back but I think I need to get one for the next time a cat or kitten gets sick. 2 minutes in the microwave and it stays warm for hours, plus no wires!
We used it covered with a towel, even though it has a fuzzy cover, but that was mostly because tiny kittens are messy.