I feel it is unlikely that they eat grass due to a need for nutrients, as even very healthy dogs on excellent diets will do it. (birdneckanimalhospital.com)
Formulating excellent diets for reproduction and growth is more difficult and demanding than formulating diets for adults. (darwinspet.com)
While easy bruising (and fatigue) can indicate a B12 deficiency, there's no doubt that some people are more sensitive than others even with excellent diet. (thehealthyhomeeconomist.com)