When buying a hedgehog house there are so many to choose from, it can be bewildering. A safe well made house is critical to the hedgehog’s survival during hibernation. If the house you buy is too small, made of too thin materials, isn’t designed well or doesn’t have adequate ventilation it either won’t be used, or the hedgehog trying to hibernate in it will die. Please don't waste your money on 'bargains' - when it comes to hedgehog houses, buying cheap really will mean buying twice.
A hedgehog’s temperature mustn’t fall below 5C or ice crystals will form in her blood and she will die. So to keep the inside of a house at 5C or more, while the outside ambient temperature is -5C (or colder) there needs to be lots of room for insulation. A natural made hibernaculum can be a metre across. A well made solid house made of good thick wood can be smaller, but must still have enough room in the bedroom section for a dense, protective wall of insulating hay to be packed around the hibernating hedgehog.
Breath contains moisture, and if the hedgehog house isn’t designed well with good ventilation which allows moisture to escape, without letting a draught in, that moisture will condense on the ceiling of the house and drip back down into the bedding, soaking it. Mould will form on the damp hay and the spores be breathed in by the hibernating hedgehog.
Hibernation isn’t a sleep, it’s a state of metabolic depression. By lowering the body’s metabolic rate it requires much less energy to function, so if enough fat is stored in the body it can be used as energy, making it unnecessary to eat. The hedgehog still has a cycle of sleep and waking (when she is conscious and aware), but her metabolic rate is slowed down so much that she may breathe only once a minute, and her heart beat is slowed to just 20 beats a minute. Bodily functions that are not necessary to life in this state, like the digestive and excretory systems, are paused to conserve energy.
Her whole existence during hibernation revolves around conserving precious energy, so the better the house is insulated, the less energy she will have to use to keep warm. I have trialled many hedgehog houses on the market and there is only one house that meets all these requirements, and which I would recommend.
Line with newspaper for extra insulation and to make cleaning easier, and then stuff the bedroom department FULL with hay (ordinary meadow hay from a pet shop or supermarket). Poke your hand in through the doorway and pat down, to make a tunnel and sleeping area through the hay. Leave more hay in a waterproof container beside the house, so the hedgehog can help herself to more. Then, most importantly - leave it alone.
Don’t be tempted to check.
If you don’t have a resident you’ll be disappointed, and it you do have a resident you’ll also be disappointed because she will no longer consider this a safe place to spend her most vulnerable time in, and will leave.
Well made of good materials this house will last for years with zero maintenance. Although there are runners on the bottom of the house to prevent the floor coming into contact with the soil, this gap will quickly be filled with worm casts, so place on a rubber mat (a cheap supermarket doormat turned carpet side down, some pond liner or thick plastic will do) to prevent damp rising. Position on level ground (a slope or dips will create puddles) in the shadiest, coolest, most protected place you have in your garden. Beneath shrubbery is ideal. Having one side of the house against a structure (a wall, fence, tree trunk or building) will make it secure and attractive to hedgehogs.