Hay 🌱 is grass with the water reduced ☀; each mouthful is a more concentrated source of calories. Hay contains seven to eight times more calories than live grass per pound. Grass is 70 to 80% water💧 as opposed to sun cured hay at 5 to 10%. If your horse is overweight, slow feeding will help to regulate insulin spikes⬆, metabolism, and secretion of cortisol. For underweight equines, it can help increase digestion and assimilation of calories and nutrients.