Rotty food/diet

I have a 93 lb. 7 yr. old rescue for about 3 years now. I don't know about her past except she wasn't cared for & neglected, she had heartworms really bad when I got her so I had to take care of that. She had knee surgery about 6 months ago so I was trying to build up her muscles with Bully Max muscle tablets, & feeding her cooked shredded beef over her dog food or shredded chicken, she loved it! But the vet feels that it's an overload of protein and not healthy for her it's bad for kidneys and pancreas. I figured I was giving her good healthy food that being a Rottweiler maybe she's a meat eater she enjoyed it. She got really sick one day & threw up several times, and when I took her to the vet they did x-rays & found out that she had a couple of little bones trapping her and some other unknown particle. I remembered one day walking her in the park from eating some bones off the ground, I didn't catch it fast enough that's probably what it was I told the vet. So now she's on Purina pro plan prescription diet kidney & meds. So my question is being a Rottweiler (I don't know if that matters) do you think or have any knowledge, experience that feeding her beef or chicken as a topping with her dog food is too much, unhealthy? The vet said 3 weeks we're going to do more blood work and see where her levels are. She doesn't like eating just dog food with some soft food on top maybe or mixed in plus it gets yucky if she doesn't eat it all & at $80 a bag you can't afford to waste! She looks forward to that meat or chicken.