Val, the treats I giver her are about an inch long so they are small. I only put a small amount of food into her bowl and after a few days I toss it. She will eat her food out of her purple tug a jug, I guess she wants to work for it. The bag of food I bought last weekend is only a 5lb bag so I want to see how long it will take her to go through. I also thought about it tasting old after that long. I have it in a sealed plastic container as well. I have noticed she will eat her kibble if I mix it with fresh cooked meat, but didn't know if this was heathy for her or not. I don't eat a lot of beef myself, I usually eat chicken or turkey. Maybe I will put her onto a measured amount and a schedule and just add the fresh meat to it and see how she does. I have heard it is not good to change up their food on them, but want her to like it.
I just want to thank all of you that have given me advise about this.
I will try a few different things and let you all know how she does.

Oh okay, treats that small shouldn't fill her up much. And adding fresh cooked (boneless) meat to her food is wonderful. That is a great idea and wouldn't hurt at all, if she likes raw you could even mix in a little raw with her food if you want. Nothing wrong with changing their food often unless you have a really sensitive dog on your hands or if you have a picky eater I tend to discourage frequent changing as it can lead to being even pickier if they come to expect it. My dogs get a varied rotation on a regular basis. When I fed kibble I would mix it with a different canned food every 3 days or so. If you do get her eating more then keep an eye on her weight to make sure she's not gaining too much, hopefully things will even out. Good call on the 5 lb bag, sounds like you're already doing really good for her on your own.

I'd like to know how long she takes to get through a 5 lb bag. For comparison, my one 6.5 lb chihuahua used to go through a 4 lb bag of Wellness Core in about 2 months at 1/8 cup per day mixed with about 2 tbsp of canned food. I can't imagine even a small female sibe could make a 5 lb bag last that long. I don't know how much exercise Libby gets but exercise is a really good appetite stimulant as well.