My girl had 5 pups nearly 4 weeks ago. She has been brilliant but after we moved them yesterday into the kitchen for a bigger area, she has blasted them a couple of times.
She seems to want to be in with them sometimes but not for them to feed all the time.
Last time she had 10 and we had to help with feeding and about this time she looked positively overwhelmed and was virtually running out of the pen. She never growled or chastised them once and I was almost willing her to.
This time with a smaller litter, things are a little easier for her and it has been so different but I was concerned yesterday when she had a pop at a puppy who did not appear to be doing anything in particular to bother her. I've had bitches who have given a warning growl but this was more of a snap.

I've had some bitches that have happily fed their pups for 10-12 weeks, yet others that wanted nothing much to do with them from 3-4 weeks of age.  The one I had a litter from last year would not feed them past 3 weeks and kept telling them off to show them there would be no more milk for them. Once they got the idea that they were onto solids and couldn't suckle anymore, she was okay with them again. Her own mother fed her pups for any number of weeks and never got fed up but her grandmother was the same -nothing past 3 weeks.

So do you ever get concerned that the pup will be affected (mentally) ?

Keep a close eye for mastitis. This was the first sign for me for a bitch that had it with both of her litters...both times at 3 weeks old. She went from a very sweet,loving mum to growling and snapping at them.

So do you ever get concerned that the pup will be affected (mentally) ?

Not at all. If anything the ones the mums weaned early had better characters than the ones that suckled late with my bitches, but I am sure that was sheer coincidence. They're not REMOVED from mum, she just has the choice of whether to see them or not (i.e. can get out of reach), and once they have understood there is no more milk from her, she will go back to playing with them etc.

I find the same at about 4 weeks plus suddenly Mum seems to be really mean to the pups and hardly wants anything to do with them it seems.

As soon as the pups get the idea that they can't demand milk anymore she becomes sweet and spends more time with them again, feeds them occasionally as and when she allows, and starts being a teacher rather than a source of nourishment.

The means bit seems to be from a few days to a week.

She seems to have been much better in the last day or so. and the pups are starting to eat some solid food which she likes to clear up while they feed from her.