What fabulous compost you could have there, depending if it is thick enough for you to rake it up. Even if you don't have a flower or veggie garden you probably have landscaping beds where it can be used. Or rake it into your lawn.
But to your question. Chickens love scratching in leaf mold and such. This could be in woodlands, under bushes, or in fence rows. They like to scratch in compost piles and some compost piles can have a bit of mold in them. If you use the deep litter method you probably have some mold in the litter. If the weather sets in wet for a while or you let the chicken poop build up enough to stay wet underneath mold often grows in it. Nature uses molds to help break down organic materials. Molds are everywhere in nature. I'm allergic to molds. My sinuses don't like it when I'm stirring things up in the chicken coop by raking or cleaning, when turning my compost pile or bagging compost, or working in the garden if I'm fooling with mulch.
Some molds can be dangerous. If your feed gets mold in it toss it. The mold itself isn't the big problem, it's more the digestive byproducts that build up as the mold breaks down the organic stuff in the feed. Most molds aren't dangerous, some can be beneficial. They are just part of nature.
I personally would not worry about possible mold in that at all. If it is thick enough and is damp enough they may find some nice treats in it. That's why they love scratching in leaf mold, they often find nice treats in it. But what's important is how you feel about it. If you are worried, remove it. Or rake it out to a thin layer so it can dry. Drying will get rid of the mold.
