Fattening up a horse but not adding energy

I have a paint mare who is very energetic but she needs to gain some fat around her hip areas (very pronounced) and the top part of her back. I don't want something that will make her anymore energetic or hyper then she already is but need her to fill out. Any suggestions would be great. Thanks so much.

Make sure she has ad-lib hayas this can make a huge difference to weight. What does she get at the moment?

You could try giving some sort of barley based mix. Alli doesn't go hyper on it but her mum does. Depends on the horse! I have found this time of year to be a good time to change feeds if going up the energy scale as they use more energy staying warm in winter and it doesn't seem to change their mentality too dramatically. Change steadily though to monitor and changes and to help her get used to it and not have a complete energy rush!

Lots of forage (grass, hay) and fats are the quickest, safest way to add pounds. Rice bran, rice bran oil, flax seed all have good fat. Hay in good quality and never ending quantity. As far as where she needs to gain her weight, sounds like a top line issue. Find hills and make use of them! Walking those hills makes for a round behind and will often help with topline issues.