Liquid water free choice. Some people like to provide warm water to their goats, even. I only do that after kidding. But, liquid water through winter is #1 far and away. Seems silly to have to say it, but it is often forgotten and frozen water that is forgotten can lead to serious health problems. A nice plastic tank with a plastic tank deicer is affordable and easy. If you must carry water to them, it means it is more of a spaced out chore, rather than a daily one as well. Can save you getting burnt out feeling or injured if the conditions are poorly. We prefer having a hose in a heated area of our barn to access.
WELL VENTILATED housing is another thing overlooked. People are not comfortable outside, so we seem to think our animals aren't either, and want to close them up. This should be avoided at all costs. What is 'snug' to us is extremely poor ventilation to livestock.
Another great way to avoid under ventilating animals is to PUT FOOD AND WATER OUTSIDE. This helps improve housing quality tremendously because animals are not staying indoors pooping and peeing and creating a buildup of moisture and ammonia in their housing. The water and feed does not need to be far away, but preferably far enough away to reduce mud get animals out and about as often as possible.
WELL BEDDED is very important. Clean and dry important, though what kind matters less. Whatever you like cleaning up on your schedule.
Doing regular 'knee tests' by dropping to one's knees is important to evaluate moisture. I usually use an ammonia reducing product like sweet PDZ in winter to help with any ammonia buildup.
Animals do best on a full rumen to generate heat. I prefer to free choice hay all year round to ensure adequate nutrition for growth and lactation, personally - so winter it's just a continuation. What kind of hay to feed will vary drastically with what animals you're feeding and your goals. Here, I prefer a quality grass hay as my base hay. Usually it has some alfalfa but that is generally less my concern. (I prefer to feed alfalfa pellets in the stand for my lactating animals to reduce waste). Animals that are not lactating and are in good body condition do not need a rich hay. Animals in the last 4-6 weeks of gestation need to be on an inclining plane of nutrition - usually optimal hay quality (very good grass hay here) as well as grain to prevent ketosis in late gestation. Young stock do well with a high quality hay +/- grain depending on age and growth goals. Bucks may need grain as they come out of rut (though tread carefully here) as well as a high quality hay to gain weight after rut. Critically evaluate your herd body condition. Thin animals will suffer the cold worse and this can mean poor gain (spending energy trying to stay warm), avoiding traveling to feed and preferring to stay indoors, (vicious cycle), poor haircoat (hypoproteinemia), and susceptibility to disease. Evaluate thin animals for concurrent disease or parasitism, and TARGET DEWORM IF NECESSARY, being aware of pregnancy and the safety of your chosen products. Also be aware the dangers of deworming whole groups due to elimination of refugia as well as interpretation of fecal egg counts as worms may be entering the dormancy period of few eggs shed. Consider management changes to prevent future thin animals going into winter and current management to alleviate current body condition for those on the thin side - more intensive feeding, parasite control, lactational/pregnancy demands or other concurrent illnesses. Blanketing those that are frail can be beneficial as well as segregation from more thrifty animals as well. In big herds, segregation by class, size, and status can help manage each group for it's ideal situation but is less feasible in smaller herds. Something to consider if you have the facilities, however.
Overall a well managed herd needs nothing super special, just awareness for the seasonal differences between spring and now. Animals that repeatedly 'need' assistance should lend themselves more towards being culled than catered to. That being said, there are environmental or management learning curve reasons why, year to year, animals may need a little assistance. Years of drought, heavy worm burden, a feed or management change that didn't work out as well as hoped, environmental or health disasters etc.
AVOID ELECTRIC HEATERS AND HEAT LAMPS. So many barn fires could be avoided this way. The vast, vast majority of animals do not need heat lamps or heaters. Animals that may benefit from them are the very ill or the very young. Even the very young, once fully dry and with companions, do just fine in almost all temperatures without supplemental heat. We do not use them beyond drying the kids. IN very cold weather like years I'm kidding out does in January, I'll often keep kids in a more enclosed area of the barn for a short period and just ensure their containment (crates with bedding usually) stay impeccably clean to improve air quality. Of course kidding in very cold weather is usually unadvised if you're not willing to put the time into tending births and drying kids. This can be nearly impossible if you're unaware of due dates.