This is for 1 bird..
Feed the bird three times a day this mixture ..the amounts are for the 3 feeds for the day..
give for 3-5 days .
1 cooked egg yolk
1 teaspoon honey
2 tablespoons plain yogurt .
3 to 4 tablespoons rolled oats . To give substance to the feed, or use chicken crumbles or...
I'm not at all convinced it's a grit problem..
unless these birds are kept in a coop, or in a very confined pen area where they can't scratch for grit in the dirt.
but..trying the grit won't hurt.
I did post in your other thread..asking for more info..and giving you info about how to know for...