I used baileys no4 on an underweight TB I had, they were great and he put on weight and condition within a couple of months and didn't make him at all fizzy.
Two recommendations from me! The yard I work at uses them for everyone with no problems.
My incredibly sugar and ingredient reactive horse is on them and when necessary can eat loads without turning a hair.
I really rate them too. My tbx needed a bit of extra condition and they've helped (along with the right training) and her coat looks loads better. Agree non-heating.
Plus good for dodgy teeth as with a bit of water added they go quite soft.
i have used 4 sacks worth for our welsh x and i think they are fab. He looks great - still a bit thin but I am going to up the amount I feed him (he has the minimum required for his weight atm), has lots of energy and is generally very happy and still chilled. Doubt I'll change in a hurry. I use the topspec comp balancer too and I might add some linseed for weight gain and shine but he's a fussy eater and he loves them so its all good!