Thanks, that's not possible,and to the best of my knowledge nothing had changed, but on closer inspection, I  can see a whole bunch of troops are missing.

The only explanation, apart from a bug, is that I deleted them all by accident instead of the few that Loki had given me previously.

The solution here would be a "decline Loki's  gift" option to save the trouble of deleting what you don't want. 

On the bright side I got rid of red food.

What had thrown me is, my other kingdom had also just been given troops from Loki, and not put me into the red for food,not noticed the  troops  that were missing,so I had thought some change had occurred. 

What doesn't seem to make sense is, if your production is shut down, why doesn't food run out? How can hero's skills,equipment increase it, when you are not supposed to be  making any?

I'd considered forging something else to test this.

XYZ, have you lost troops in a reinforcement or on a few marches? That's what I would go for.

One thing that happened to me was I used to be outside the clan stronghold area and my food was red. I moved To clan stronghold area and my food was ok.

Thanks for the input, but it would seem that you haven't followed the thread.

 I thought, but incorrectly, that I had covered all options before I posted my question.

None of your suggestions were possible, any loss of troops like that should produce a  battle report, there should be survivors,and there were none, of course that could be caused by a bug,as well as being an explanation for their disappearance.

I have no definite proof, but the only explanation would be the one I already came up with, that I accidentally deleted all of them,instead of just the few of them that were surplus. 

Yes, many things, like moving your town inside the valley of the Aesir can affect production, and it is the kind of thing you might not immediately notice, and later wonder what caused it,just like what happened with me.