
A little liquid paraffin should help with constipation. she is probably sore from the straining.
I would look at how your feeding and ensure enough liquid is being taken in. If she isn't drinking well then soak the food more.
> the littlest which also happens to be the one we are keeping
> I do wonder if she is the right dog for us but we know no one will pick her as she is not the colour variation they would want for this particular breed.
As long as she is fit and healthy the fact she is the wrong colour does not make the the right choice for you to keep.
I assume this was a planned litter, and your aim was to improve on her parents, therefore you should be choosing the puppy most meeting the breed standard, especially if you are intending to breed on from her to further the line. A breeder should only be keeping the best to breed from to maintain the quality.
Also breeding from an unacceptable colour will only ensure it is more likely to appear in future litters.
Keeping an extra puppy that will not be useful in your breeding plans will hamper you in your breeding efforts, whereas she would be perfectly fine in a loving home, even if you reduce the price for a mismark, though to be honest plenty of people are drawn to the different puppy in a litter,a nd as long as the colour is not a health issue then it matters not for a pup that will not be bred from..