Twice a day, and properly cleared
In a hard frost, a field trough can skin over within hours of being cleared, which is why the check belongs at both ends of the day: before morning turnout or feeding, and again in the last round before dark, so no animal faces the longest, coldest stretch of the night with sealed water. The technique matters more than owners expect. Break the whole sheet, not a token hole, and lift the broken pieces clear of the trough and onto the bank — chunks pushed down or left floating chill the water around them and seed a faster refreeze, and many horses and cattle drink noticeably better from a trough that looks like water rather than a slush puzzle. While you are there, check the trough itself: ball valves freeze, supply pipes split in the first thaw, and a trough that is icing faster than its neighbours is often a trough whose inflow has stopped.
Slowing the freeze between checks
Checks alone lose the battle in a real cold snap, so build in the small physics that help. A floating ball — a football or similar — bobs with the animals' drinking and any breeze, keeping a patch of surface moving and giving stock a point they can push down to reach water under a thin skin. A length of log left floating does similar work. Insulating the trough sides, sinking part of it, or fitting a cover that leaves a drinking opening all cut the rate of ice formation far more than owners expect, and a thermostatically controlled trough heater, installed safely and checked, ends the problem for the worst weeks where power reaches the field. What does not work is salt or anything added to the water, and anti-freeze of any kind near drinking water should never be contemplated.
Ponds, ditches and the ice that must never carry weight
The dangerous misunderstanding in winter fields is the pond. Livestock that have drunk at a pond all year will walk toward it in winter, and a horse's weight on ice is borne at four small points — hooves punch through ice that would hold a person, and a horse through pond ice in deep water is a rescue very few yards are equipped to make. So the rule is absolute: no animal should ever need to test pond ice. Fence ponds out of winter grazing or close them off with tape and posts before the first frost, and provide trough water they reach first. Check ditches and gateways too, where thin ice over shallow water breaks legs rather than drowning animals — a fractured fetlock from a hoof through ditch ice is a common and preventable winter injury. After a thaw, walk the same spots again: melting ice overhanging a bank edge collapses under a drinking animal that was perfectly safe on it the week before.
Water is a welfare check, not just a chore
Frozen water does its harm quietly. Animals that cannot drink stop eating properly, horses on dry winter forage are prime candidates for impaction colic when water intake drops, and a herd can be mildly dehydrated for days before anyone connects the dull coats and dropping dung balls to the trough. So the ice round doubles as an observation round: are the animals actually drinking when the trough is cleared, is one individual hanging back, has dung output changed? Keep a simple record through a cold spell — which troughs froze, how thick, any animal not seen drinking — because patterns across a week tell you where to spend money on insulation or a heater before next winter. And roster the round like the welfare job it is: on KinsLe, Care Teams lets the yard assign the morning and evening ice checks to named people through the cold spell, with each completed round marked by a timestamp, so a missed check in the middle of a freeze is visible the same day rather than discovered at the trough.