I am hoping you can help me?

I have a bitch who isn't the best eater in the world. She tends to eat as and when she feels like it, i have tried very thing. My concern is she was mated 4 weeks ago and her lack of appetite is now worrying me, as if this will the affect the pups. She is very reluctant to be hand feed, i don't want to stress her out any more than i have to. She will eat something for a day or to then she will not touch it again, i don't think i have helped but not i am paying for it.
She is healthy, she seem to eat enough, she never has been a great eater.
Thank you ahead for your help

Emma