the runt of the litter is still feeding ok but not as long as the others think I might try and help her a bit. What do i need to buy? is it lactol?

I will be interested to see other people's replies, but if I have a little one, I tend to keep it on mum's milk.  I just make sure that it has plenty of opportunity to feed and latch it onto the back teats.

echo that.  Get her onto the back teats before the others feed if possible.

Also agree, mum's milk is best, the smaller pup will not eat as much as the other's anyway having a smaller tum, just pop on the back teat first the minute she wakes up. Not all pups are meant to be the same size. :-)

Put her on Mum more often.  Being small she tires more easily.  If Mum is at the stage of leaving the whelping box between feeds then half way through I would put the wee one onto Mum by herself.  Do this all through the day at least every two hours and she will catch up.

Glad to see we all have the same thoughts!

Also agree, mum's milk is the best ;)

It is more time consuming than bottle feeding but putting the smallest pup on mum before the others start feeding and supervising them gives that one a head start ;)

I have been putting her on more often and on her own today.

Hi
our litter is just over 3 weeks and the last pup born was slightly smaller and lazier than the others.  I was initially worried about him as my bitch Cassie was quite rough with him I think now because he was so sleepy.  Looked like she was stimulating him by being so rough.  I would watch with frustration and a little horror as she'd pick him up (he'd be squealing)and drag him round to the other end of her bed away from the rest of the litter, she'd almost have to throw him between her back legs to the bigger teats and turn her back on the others.....and only when she seemed happy he'd had his fill would she allow the bigger puppies to feed.  This went on for a few days, she'd keep pushing and flicking the rest of the litter away with her hind legs.  He isn't the smallest puppy now! he's lively and alert and all credit to Cassie.  I'm just glad I didn't intervene, but allowed mum to do her job.
It never ceases to amaze me how natural and instinctive it is for our bitches to rear their pups, seemingly knowing exactly what to do and when to do it.

That's amazing :)  I think you were extremely lucky there .  In my experience it is the breeder that has to take action as the bitch will not, either due to ignorance of the pups special needs or an affinity with how nature would have worked things out prior to man's interference, I don't know.