Five week old kittens - Weaning and Litter Training

My cat Harvey had 3 kittens five weeks ago today. All three are doing well, have teeth and are happily exploring their home.

At the moment though, none of them show any interest in food, and their mother is still grooming them to make them do bowel movements.

There's absolutely no sign of them beginning to wean from her, we've tried to see if they're interested in eating kitten food, either by watching their Mum eat or independently.

Should any of this concern me, and if not when should I become concerned about their lack of development in this area?

Other than these two issues they appear to be very healthy and happy.

They were born a little early though at about day 54-57 of their Mum's pregnancy, and based on stages, appear to have been slow to develop at all stages - they appear to have been about a week behind in opening their eyes/ ears and starting to move around. Is this just another symptom of them being a little premature?

Remarkable they survived being born so early, under day 60 aren't viable in the vast majority of cases, being hairless and organs not developed.

They may be a little delayed, continue feeding mum in the kitten pen, and of course have her litter in there as well. They'll toddle over when ready and start eating, hopefully you're feeding wet or raw - this is best to start kittens on. 

I just double checked the calendar, and what I should have said was that they were born somewhere between the 57th and 60th day. I'm clearly not that good at maths!

When they were born, they had some fur, but it was very very short.
 

Yes I agree with missymotus, it's the same for premature babies, born a month early they are behind, developmental growth is before birth so they just need to catch up. So they are more like 4 weeks of age basically.

Not sure if they are crated or have free roam, and my advice is for crated kittens since I have a rescue group and crate all moms and kids.

Although they are capable now of pottying on their own, Mom will continue to lick their butts as part of her nurturing duties, until their poop is more than she is okay with, but by this time they will be hopping into the litter box assuming the sides are low enough for them to have easy access.

Moms food and water dishes should be low as well and accessable to the kids, because she will have a tendency in a couple weeks to begin tiring of nursing them and separating herself from them, or you will start seeing her laying in an upright position so they cant nurse constantly.

If allowed, kittens will still nurse even after they are eating food just for the security and comfort factor. Up to 4 months even, but usually by then mom says no more, since their teeth and strength get to be very uncomfortable for her.

I can only go by my own experience with Goldy four years ago. She had 3 healthy full-term kittens. I did keep a written record of each kitten, so I know they started eating little bits of solid food between 4 and 5 weeks, but mostly momma cat ate the food I put out for the kittens. She did not appear to start weaning them until they were over 6 weeks old and even then it was a very slow process. A couple of them were still nursing occasionally at 16 weeks.

Since your kittens were premature I wouldn't push them to start solid food yet. Their little tummies may not be ready to handle anything except mother's milk. You can put kitten food out for them and if mom cat eats it, it's good for her too. Babies will learn how to eat from watching mom as fast as they will if you try to teach them.