My kittens are 3 1/2 weeks old and I have not started weaning them yet, one of them got out of the nest for the first time yesterday.
I was planning on soaking dry kitten food in boiled water and allowing it to cool.

When do they start to poo? Is it when they start eating solid food? As of yest, their mum just licks their bums to make them wee.

If this is the case, then I was going to wait till they are able to get in and out of their nest before weaning them, so that they will be able to get to the litter tray.