How do you keep tiny thin bits from cracking in the kiln?

The cracking in small protrusions is almost always a battle against uneven shrinkage while the clay is wet. Since you are dealing with delicate, thin sections like ears and tails, they dry much faster than the main body, causing internal stress at the joints that leads to failure. You are correct to be concerned about the drying pace in a dry winter environment. When working with small, fragile elements, the primary goal is to keep the moisture loss as consistent as posible across the entire piece. My experience suggests that covering your work loosely with a thin plastic bag or even a damp cotton cloth works really well to slow down the surface evaporation, allowing the moisture to distribute more evenly throughout the piece before it gets fully stiff. Regarding the joint attachment itself, scoring and slipping is the right way to start, but it might not be enough for these super thin pieces. If they are truly delicate and fine, sometimes building them slightly thicker helps them handle the stresses of drying without snapping off. Instead, instead of just relying on a fine slip line, try building up a slightly wider, more substantial collar around the point where the ear meets the head. This creates a transition zone, essentially giving the thin piece a cushion so it doesn't have to bear all the stress of the body's shrinkage right at its base. If you are still getting loss, think about whether the cracks are happening while leather hard or if they are appearing during the firing process. If they crack while leather hard, the issue is defintely uneven drying or insufficient clay body elasticity. If they appear in the kiln, it might be related to thermal shock. A slower, more controlled firing schedule usally resolves that. But for the hands-on part, focusing on that transition zone and ensuring your studio doesn't blast the piece with dry air is what solves this issue most frequently.

I don't think building a wider collar around the attachment is the ultimate fix for this problem. Focusing on thickening the joint just adds stress where it's least wanted, and you might find the new bulk cracks separately. I'd argue that if the clay is struggling to transition between the thin ear and the main body, it suggests an internal weakness in the body itself, not just the joint. You need a consistent clay mix that handles rapid changes in section thickness better overall. Have you tried blending in some grog to see if that reduces the overall internal stress instead of just building up the area?

I totally agree that you need to manage the drying pace so the whole thing shrinks evenly. That moisture consistency is critical for small details like thin tails. I've found that simply covering the entire piece with a damp cotton cloth works better for me than trying to seal it in a plastic bag. It keeps the humidity around the piece high without trapping too much heat, which stops those stress cracks from forming at the joint while the clay is still soft.

Update: the damp cloth trick sorted it. I'd been loosely draping plastic before but it wasn't doing much, so I switched to a damp cotton cloth over the whole piece and the ears stopped cracking. Also thickened them up slightly on purpose, which helped too. Lost zero out of the last six, so I'm calling that a win.