Most sheep and cattle are greedy and at this time of year constantly on the lookout for hay, silage or concentrated feed, but that isn't their natural behaviour. The diet they have evolved to eat is grass and farmers have to train them to eat those man-made foodstuffs.

Most farm animals learn fairly quickly to relish supplementary feed, but some disdain the farmer's offering and stand apart from the rest at feeding time. That's quite rare in cattle, but not uncommon with a minority of sheep.

Hill sheep can be the worst offenders. There's nothing more annoying than seeing non-feeders stand aloof while the rest of the flock tuck in. Invariably they will become very lean in a harsh winter and give birth to small, weak lambs that perish from hypothermia in a cold, wet day. That's because such lambs have a surface area that is large in relation to their body mass and they quickly cool down.

Worse, in a cold, late spring as we had last year, lean ewes don't have enough colostrum, that vital, highly nutritious, first milk that starts the lamb's digestive system working properly as well as passing on immunity from its mother to various diseases. Even if a thin ewe manages to fill her new-born lamb with colostrum, she may subsequently fail to produce enough milk to successfully rear it.

Ewes that have little or no milk invariably abandon their lambs. That is nature's way of ensuring that the ewe survives.

Lean ewes are also more prone to illness, so it is important to introduce pregnant ewes to supplementary feed in the run up to lambing.

The best time to train animals to feed is when they are young. It's amazing how quickly a young lamb learns to mimic its mother and nibble beside her at the morning feed.

Another reason it's important that sheep learn to eat supplementary feeds is that it allows farmers to quickly boost their rations when a snowstorm or prolonged bad weather comes along.

I always used to train replacement ewe lambs to eat out of a trough in the autumn. The idea was to keep them in a small field that was short of grass, as they learned a lot quicker if they were peckish - hunger is always the best tutor. Another trick I used to deploy was to put a score of older ewes in among the bunch of trainees to show them what it was all about.

Most crossbred lambs learned to feed within a week to ten days as they had experienced feed with their mothers when they were young lambs. It was those that had been bred on high hills where their ewes were not fed concentrated feed, that posed the biggest problem.

At commencement of training lambs to feed I would round them up every morning and keep them huddled round the troughs until all the feed was consumed. After about a fortnight I walked off those that refused to feed while the rest were busy guzzling, and put them into a shed. That had the advantage of denying them any grass to eat and keeping them in close proximity to the feed troughs and hay racks. Despite all that encouragement there were always some that stubbornly refused to eat and had to be culled.

I firmly believe in feeding sheep the best. Inferior feed may be cheaper, but at the end of the day costs more as it may not be as palatable or nutritious. As a result, the sheep don't perform as well. Cheap feed proves the old adage that you only get what you pay for.

Once trained, feeding time can be bedlam. At the slightest sound of an approaching farmer or shepherd, hungry sheep congregate in a mad rush to be fed, creating a situation that can be like trying to walk against the flow of a football crowd, and involving a lot of skill and fancy footwork to avoid being knocked over.

It you aren't quick enough off the mark, you're soon engulfed by the mob of ravenous sheep. Often they ca' the feet from under you, and you suffer the humiliation of being trampled underfoot.

It's the mud that often surrounds troughs in wet weather that makes things so difficult. Sheep have four small hooves, one at each corner of their bodies, making them very stable and sure-footed.

Ungainly man on the other hand slithers about on two long legs stuck into a pair of wellington boots. So every time he tries to sprint ahead of the sheep as they follow him down the line of troughs dispensing feed from a bag, he risks slipping in the mud and being overwhelmed.