Bubbles mentioned in passing :

Also - consider wrapping the houses in plastic for a few days, giving
them a _very_ slow dry - possibly helping to avoid unevenesses that
result in cracks when firing.

I have been doing other miniature work, progressing the detail of
carvings in drying clay, and I've used plastic storage containers to help
them dry evenly. I have never had problems with cracks in firing, but I
always assumed that I would and work to avoid it.

I failed to mention that my intent is to make fairly small houses,
N-Scale (1/160).