A.T.
Mine did that too---guess what? She had a urinary infection. We let it go for ages (since she was about your kittens' age) thinking she was just being a little pisser. When she runied 2 pairs of $175 shoes we took her to the vet. I felt like the worst cat owner ever when the vet said she had a very bad infection and had probably had it for a long time. Take your babies to the vet and make sure nothing's physically wrong before trying anything else. Luckily there are injections they can give them instead of pills. If it's not that---then you can figure out what else might be the problem.