I don't know, but you could offer it in a separate dish and see what they do.
That depends on what minerals you want to provide. The pink salt is mostly salt, with only very small amounts of anything else.
You might consider something like this:
https://www.fertrell.com/poultry-nutribalancer
This is meant to be a complete vitamin/mineral supplement for poultry.
There is a link you can click to get the nutrition information (it's only about 1/10th salt).
There is another link to a page of "recipes" for feeds that use it with other ingredients. The poultry feed recipes are designed to make 2000 pounds at a time (one ton), which is probably much more than you need, but they can give you an idea of what one company considers a useful set of ingredients and proportions for chickens of various ages.