I have one chicken in particular that is quite weak and I believe sick. Long story short, I am trying to find the right Calcium to feed her separately. I've seen some videos saying you can take chewable calcium tablets for humans, crush them up and mix them in the food with some water. I was willing to try this, but am not sure if those pills are alright for animals. Does anybody know of a suitable calcium source I could use besides Grit shells? Something I can get at a regular store would be great.