I put my girls on fish oil as a source of omega-3s and they shedded out like shiny pennies this spring. There are (obviously) calories in it, but it isn’t as bad as you would think. I gave my 900lb mare two 1 oz squirts a day. The calories in 2 oz is about equivalent to 1/4 scoop of oats. She’s an easy keeper too and only gets enough feed to hold her supplements!