Here is some information taken from https://www.hedgehogstreet.org/ on hedgehogs and hibernation.

Hedgehogs usually hibernate from October/November through to March/April. Research has shown that each individual is likely to move nesting sites at least once during this period and so can sometimes be seen out and about. During mild winters hedgehogs can remain active well into November and December.

While in hibernation the hedgehog’s fuel supply comes from the fat stores it has built up over the summer. Eating enough before hibernation is vital and this is when supplementary feeding can prove important to hedgehogs.

Any disturbance during this period can be extremely dangerous, as hedgehogs use up their precious energy reserves in order to become active again.

Are they hibernating or dead?

Of course when a hedgehog is in hibernation, it will be very still and usual signs of life such as breathing will be almost undetectable. If a hedgehog is in hibernation, it will be tucked away in it’s nest, curled up in a ball, and involuntary reactions will remain. By that we mean you could very gently touch the hedgehog’s spines and if it’s alive you’ll see a slight ripple of the skin and spines in response to this. If a hedgehog is out in the open and looks to be hibernating, it has either sadly died or it’s extremely unwell, in which case you can call BHPS for advice.

We hope this information helps should you see a hedgehog out and about during the winter.

From

Harrysmuir Hedgehog Champions