Can I give my 2yo essence of chicken?

According to this article, you can give your child chicken essence from two years on: http://sg.theasianparent.com/dr-dana-elliott-when-can-i-feed-my-child-chicken-essence/ Here's another link for making it yourself using black or kampung chicken (otherwise seems similar to the link provided by Diana): http://www.submerryn.com/2014/05/homemade-chicken-essence.html

Yes, but I will recommend you to DIY chicken essence yourself. It is healthier and without preservative. Here is the recipe, it is very easy http://jewelpie.com/homemade-chicken-essence-to-relief-tiredness/

yes you can. I steamed my chicken essence with cod fish for my LO so he doesn't reject the chicken essence

Yes you can if your child would take it. My boy wouldn't even get close to it.