Thin Forelock Sign of Deficiency?

Can a thin forelock be a sign of a deficiency in their diet? All of my horses forelocks seem to have thinned out over time. Other than that, they are in good condition.

They are on a regular worming schedule and are stabled every night with turnout all day. I have recently switched from a salt block in the pasture to loose trace minerals designed to supplement my area/local grasses. I top dress their grain with it to make sure their getting their minerals! They get oats with handful of corn and cocosoya oil every night and free choice of hay in the barn and pasture. They are sleek and shiny in the summer but now have their long, winter coats but their forelocks haven't thickened any.

I probably just worry too much but thought I would ask!

Do you brush/comb their forelocks regularly or have plants/schrubs/trees in the paddock that they can catch it on?

I've never heard of mineral deficiency causes the forelock to thin.

Thanks! That's probably it, I spend more time on their body, legs and feet than I do the face and forelock. I read about a product, Shapley's MTG, that I might try to help things along.

MTG works wonders if you read the instructions for what you want to do and follow them. It smells horrid, but it's worth it.

How is their hay fed? Are they rubbing their heads when they eat?

My paint has a tiny forelock but he doesn't have much hair anywhere really. My draft has a tiny forelock which is weird because he has a thick mane and a huge tail..... I don't remember him having such a tiny forelock as a yearling so trying to decide if it has gotten smaller or he's just gotten bigger now at 17.3+!!

Make sure you use some sort of detangler when you brush/comb out the forelock so you don't break off any hair.