You could weigh 15 kibble pieces and then weigh the chicken to the same amount.
You could use parsnips and broccoli with the carrots and chicken, these are low in calories but all are high in antioxidants that will help her immune system, broccoli is high calcium too, and all are great for vitamins. The thing that we need to be carful of is not giving too much vegetables as they dont digest large amount of plant matter well so maybe do a little bit of each different veg a night, and perhaps 4-5 bits of biscuit, just to make sure the nutrients are all there, but without having such hight amount of the carbohydrates. And the chicken with the antibiotic, that makes up the 10 bits of biscuit.
Does this make sense ??
Its just an idea of course and can be worked on.