I don’t know about the fermented feed or milk. My welshies eat almost anything. They run the horses off from their feed. They steal the fish food when it’s floating on the pond and will run the cat off his food too. I give my the option of crushed oyster shells for egg strength. The Welshie eggs are about the size of a jumbo chicken egg. They are frequently thin and squished early in the season.So far I've gotten two eggs within a week. I don't know who it is but I'm pretty sure it's a Welshie since the Saxony ducks lay some whoppers and this one was only the size of a large chicken egg.
I've started feeding a lot more fermented feed, and also raw milk and cat food.