We at Vypark work with you to keep your horse safe the main consideration when selecting fencing is that it keeps your horse/pony safe and is big enough to stop jumping or fighting with neighbours, low enough to prevent foals and ponies from getting underneath.
The fence must be strong enough to prevent horses from pushing through it or using it to lean on whilst grazing in another paddock (because we all know the grass is greener on the other side).
A general guide for post and rail 3ft 6″ – 4ft 6″ (1.08m – 1.38m) for horses and 3ft 3″ – 4ft 3″ (1m – 1.3m) Ponies. Lower rails should be 1ft 6″ (0.5m) above ground level.
Stallions have their own fencing these can go to 6ft (2m) with electric top wire, especially if in vicinity of breeding mares.