Any idea's on what to feed my 7yo tb? (grass trouble)

Ok, so Mitch is a 16.1hh 7yo thoroughbred gelding, and since being at our house he has trouble keeping the grass inside him, and in saying this I mean obviously he wasn't brought up on rich grass, because if I give him too much it goes in one end and out the other very quickly.
Right now he is not in work due to a hoof abcess, but when he is in work he will be an at home showjumper and paddock dressage horse until I have the confidence to take him out, so lets say he'll be in medium work.
I wouldn't classify him as a hard keeper, but seeing as he can't keep too much of our grass inside him, obviously he's going to need something else.
-Note, he had full access to hay to help bind him up, but our supply is fast running out and right now nobody is selling any, so that's not an option right now.

At the moment he is not getting heaps of feed, about a full small bucket once a day, seeing as he's not in work. His feed so far consists of:
About 3/4 bucket of Fibre pro and a scoop of gumnuts (Because I already have gumnuts from when we had bubbles, I may aswell use them)
He is also on 45g of Strong Hoof once a day, to help prevent future hoof abcesses etc.
I also have the option of vegetable oil to give him, but I don't know about dosages etc so I haven't started that yet.
I have been putting a cap full of apple cidar vinegar into his feed also.

Is there anything apart from hay that would either help keep his grass in him, or just anything in general you think could be of some help?


I know there are people out there who are more experienced in feeds than I am, so help would be appreciated (people at my feed supply store aren't very helpful at the moment). Thankyou :)

If he's already having issues with loose stool, I wouldn't add vegetable oil. You could try a hay stretcher if you cannot find hay to buy. My TB was having pretty loose stool for a little while and we put him on U-gard and since then he's fattened up and his stool is normal.

But my Tb was also showing other signs of belly upset (possible ulcers), such as he would sweat for no reason in 40 degree wheather, the loose stool and he was irritable while riding.

I feed 1x a day
1/2 scoop of sentinal lifetime
1/2 alfalfa pellets
1 scoop of u-gard
And garlic for flies.

My horse stays plump just on that little bit.