Inspecting hives in the winter can be difficult. You want to avoid opening the hive and allowing cold air in which will kill many bees.
I've found a good way to monitor the hives without causing any disturbance, using a less than $25 endoscope available from Amazon. Link below.
While it doesn't give you the ability to do a complete inspection, it can answer questions like "Are the bees still alive, or do I need to order a Nuc". It can also alert you to rodent activity, and let you verify the main body is being kept clean (no dead bees piling up inside). Plus, being able to see the bees in the hive without disturbing them is pretty cool.
I find this is particularly well-suited to Top Bar hives which are particularly susceptible to cold.
Hope this helps any aspiring beekeepers out there.
https://www.amazon.com/Depstech-Semi-rigid-Inspection-Megapixels-Waterproof/dp/B06WRNGYXY/ref=sr_1_3?ie=UTF8&qid=1519400198&sr=8-3&keywords=depstech+endoscope
