There are several variables with clipping
1. Is the horse stabled overnight?
2. How much work is he/she doing?
3. Do you have a New Zealand Rug?
Look in the How to section there is an article on clipping a horse there.
This horse has had the neck and shoulders clipped and would continue to live out providing it was rugged. You could alter the line on this clip, leave more on the shoulders, and take more off the belly. Your pony could still be keep it in a field providing the field is sheltered i.e. not exposed to the North or East wind.
If you trace clip your pony, he will need a stable it overnight, because you have clipped his bottom. Ponies turn their bottoms to the wind and rain to help keep themselves warm.
There is an Icelandic X mare at our riding school that has a very low ‘bib and braces’ clip (same clip as the strawberry roan in the picture but a much lower line) she is kept in the field without a rug, BUT if the weather turns cold or wet she is stabled overnight and only let out during the warmest part of the day.
Finally if you have never clipped a horse before yourself and you have no idea how your pony will react to the clippers find a friend with experience or pay someone experienced to clip your pony for you. Getting horses/ponies off on ‘the right foot’ with clippers is very important. Horses/ponies that have been frightened by clipper are an absolute nightmare for the rest of their lives.