Is my horse too fat?

Blue Cross use a version which assesses characteristics such as fat palpable over bony areas the shape of the neck prominence of backbone and pelvis shape of rump size of thigh gap and angle of cavity behind the tail. They work on a scale of 0 5 horses scoring 0 are likely to be barely alive and those scoring 5 to be morbidly obese.
What does a score 3 horse look like?
A horse of ideal body condition is described as having some fat palpable beneath the skin neck muscles which are not starkly defined and as having a neck which flows gently into the shoulders without obvious interruption. The withers are rounded and the back is either smooth or forms a slight ridge. The ribcage should be easily palpable but not visually obvious. The hind quarters should be nicely rounded and the hip bones just visible.
For a more indepth look at the body condition scoring chart take a look at the BEVA Horse Body Condition Chart
Should you believe your horse to be either over or underweight it is helpful to view the entire scale and compare them to each of the pictures.
What do I do about a fat horse?
Firstly it is important not to starve a horse for quick results. This can cause all sorts of health problems including gastric ulcers especially where restricting forage is concerned. Slow and steady changes are safer kinder and usually reap longerlasting results. Making a plan with your vet to include dietary changes and exercise regimes where possible is by far the best way to approach the situation.