I usually do the adding water to dry food at 4 weeks also.... This last litter (Pebbles') didn't care for it... I then added baby food to it.... they didn't like that either... by the 5th week I had them on the canned puppy food.... by the 6th week they were weaned from mom and ate anything and everything... dry food included.
4 weeks is a good time to at least start them lapping at food so they get the hang of it.
Good luck.
