It's important to keep your family warm while there is frost outside but please remember your pets as well.
Make sure they have fresh, not frozen, drinking water. For animals that live outside, you may need to replace the entire bottle every day while the other one defrosts. A bottle snug may also help. Move hutches to a sheltered position, or into a shed if possible. A lot of people bring their guinea pigs and rabbits inside for the winter; there are special indoor hutches available if you don't want a huge wooden hutch taking over your living room.
If they are going to stay outside, make sure they have plenty of warm bedding ( hay or straw is best) and think about investing in a hutch hugger to protect your pet from extreme weather.
Cats that live most of their lives outside in the summer usually develop an attraction for sofas and beds during winter, but if your cat can't or won't come in, then make sure they have access to some sort of shelter. You can get special 'Kat Kabins' to provide a warm, cozy, insulated den for cats that may be outside when it's cold.
And for our canine companions, consider a dog coat. Formerly the trademark of spoilt handbag dogs, these days many respectably sized hounds are showing off their fashion sense when they take their owners down the local park. Not only are they almost essential in winter for thin-haired slender breeds such as greyhounds and lurchers, but they eliminate the need to wash the entire dog when Rover finds something revolting to roll in. When it's muddy, rainy or cold, then a warm, water proof coat makes life easier for almost all dog owners.
