Well the churning and bubbling sounds fine, it's just the smell that doesn't. I looked up the Layena and the website says no animal protein and no fats so there goes my theory about the fish meal. I guess try again. If you get that same smell again maybe it's just the feed and you could try and give your chickens a little bit and see how they react? From what everyone says here on BYC, chickens have a pretty good sense of what's good and bad for them so if they eat it and they seem fine maybe it's ok? Good luck