Ducklings: Niacin deficiency, too hot, or something else?

[TSOWOATNKC]

I have 3 Cayuga ducks/1 drake, and 1 Pekin that hatched almost exactly 2 weeks ago. I also have 2 geese and a gander that hatched 1 week ago. Initially, the ducks and geese were in a smaller brooder box inside but they were getting pretty cramped, so I now have them all together in a large metal trough that has pine shaving bedding on my covered deck. The shavings are changed each day, they are on the Puriana Flock Raiser, and they have plenty of clean water. I change the water daily if not more often. I noticed yesterday while drying them off after their bath that the ducks (not the geese) have what looks like cracks on their feet. I wondered if it was a Niacin deficency so I gave them peas and nutritional yeast yesterday (they also had some spinach, a little tuna, and of course grit for good measure). They have 2 heat lamps on a dimmer switches set to a fairly low temperature right now. It was a bit higher before because the goslings were so young. Its been in the 40s at night here, and around the 60s during the day so I figured that they would need the extra heat. I have been watching their behavior and they were clumping up together, so I tried putting one lamp at a higher temp and one at a lower temp a fair distance from each other to see which they prefer. I don't think temperature has much to do with it, I think they just like to sleep in cuddle puddles.

I wanted to ask the brain trust here if they know what the issue might be. Whatever it is it started quite recently, and is only effecting the ducks. I need to get new bedding in the next day or so. In the past, I had my ducks switched to fresh cut very tall grass as bedding and changed it out daily when they were big enough to not get lost in the grass. I'm wondering if the bedding is the issue, its a Niacin issue, or something similar. I don't think its bumble foot, but obviously I could be wrong.

I'm going to reply to the thread with photos in just a second (they're on my phone and I'm posting from a computer).

 

[TSOWOATNKC]

 

[CayugaJana]

I would keep an eye on it. I’ve had my Pekins and Cayugas feet look like that. It’s kinda like calluses where the pads get tougher. If they get worse and are limping, then maybe I would treat. But it looks like normal wear and tear to me.