i have an 18 yr old that possibly foundered over a year ago.he had excessive bruising on both front feet.he is doing wonderful, but i just recently purchased a home with land and i don't want to let him eat too much.what is a good time line for him to gradually be out 24 hrs a day.also, how much hay should he get if he's in the barn during the transition?thanks.
First, congratulations on the new home. I hope it's a happy and fun homecoming for you and your horse, every day.
Now, if this were my horse, I would go very slowly since there was a previous case of founder (that you suspect or know of) and because he's over 15.
Also, make sure to inspect the grass/field for any poisonous weeds or foriegn objects that the horse might get hurt on - before he gets turned out. If you're not sure, ask for some help from the local argicultural extension or even your vet or trainer.
Also, it's a little hard since I don't know the conditions of the field - as a horse on two acres of lush grass by himself, or if he is on twenty acres of scrub grass. You'll have to gage a little of this by yourself - but I am going to base it on a field that is green, occassionally mowed, and "looks like" an average horse pasture (at least 85% coverage, and about 1 acre per horse, with possibly a spare field for field rotation.)
Personally, I would start "at grass" with him for about 15 minites or so, and slowly increase it by another 15 minites or so every three or four days. If he runs around at first, it's okie to just measure the 15 minites when he starts to graze.
I would be very reluctant to keeping him at grass all day, 24 hours because of his past history. If you want him out 24 hours a day, then I would consider a smaller paddock where he has less access to grass, but more access to being able to walk or move around. I, perhaps at some point once I knew his habits, decide to allow him to go out at night first, then start turning him out from say, 8pm to 8am. Typically, I feed my horses two flakes of hay a day (one at each of his two feeds a day), and reduce or eliminate it entirely depending on his weight changes over the period of one to two weeks. My changes are slower ones, rather than faster ones. If I change anything by adding too much - too fast, I know I risk a case of founder.
Depending on his work schedule, I would be inclined to cut out all grain or sweet feed, or at least most of it - and feed primarily hay and then grass. And I would slowly change from hay to mostly grass.
If I saw a weight loss, only then I would add back a little grain at a time, or increase the amount of time he's in the field grazing.
For me, this is one of those cases were less is better (at least for awhile.) I want the two of you to enjoy this experience for a long, long time.
Oh - also, at any sign of dirreha, and I would stop the grass for awhile and go back to (all) hay, until things got a little more stable again. Dirreha is an indicator that the grass is probably too rich, and that he might be getting too much of it - especially if it's fresh, lush green grass - and his manure is loose and bright green as well. After things return to normal, I'd cut back the amount of time a bit, and then find something "safe" again, perhaps spending more time in a "grassless paddock," just so he can get the exercise and be out of the stall.
Hope this helps!