If it is just the scum on top before you stir, it is fine. Does it actually look like mold? Mine was in a cooler cabinet and was always fine being stirred once per day. Now it is in a little warmer cabinet and gets a little more scum on top but smells fine. I still stir once per day. I do the 3 jars rotating through each day. I have an easy schedule. I have 3 jars fermenting and get up early to feed. I get my 4th jar that is washed and ready. I put 16 oz. filtered water in it and put 2 cups of my dry feed in and stir with my silicone spatula. I line my other 3 jars up to the left of my clean jar putting least fermented then more fermented to the left of each, so they are in order with the one to feed that day furthest left. I take my spatula out of the newest jar and stir the one next to it on the left, then the next, then put the spatula in the one ready to feed. I feed my girls about 2/3 of the feed directly on the ground in a few small piles of the run then bring the jar in leaving the spatula in it. I put all the jars back in my cabinet. In the afternoon, I feed the remainder of the fermented feed for the day with the spatula still in it. I wash my jar and spatula, so they are ready for the next day.
My flock is doing well. 4 of my 5 girls are around 31 and 32 weeks old. My Sicilian Buttercup is a few weeks older. My Barred Rock is around 32 weeks old and just molted for 6 weeks and looked beautiful the whole time. She just started laying again yesterday. All are laying except my Easter Egger which should start laying anytime. She is finally old enough to start. I feed my girls fermented feed twice per day and give dry food freely late morning to early afternoon in case they are hungry. They get a few sprouted lentils daily, and I just started sprouting alfalfa seeds a few days ago to try. They will be ready to eat tomorrow. They get to free range in my small yard and garden 1-2 times per day. Yes, they are a little spoiled but are sweet, happy girls! I thought I would share in case anyone wants to know what is at least working with a simple way to do fermentation for someone who wants to give it a try. I love it! Enjoy!