Originally Posted by loghousecountry
He was on grass...about 100 acres that he had free run of.
Could that have possibly caused the founder? Or contributed to it? I'd just take it easy for now, don't restrict it completely but maybe just until the vet gets there only let him out part of the day, or with a grazing muzzle (although from the sounds of it with the way he eats hay he may not have been getting much to eat anyway). I don't know what part of the country you live in, but around my neck of the woods the fall grass is getting pretty rich.
The vet would have more knowledge about what the real issues are and how to handle them, since he can see him up close and personal, which the rest of us on here cannot :)
And like others have mentioned, getting his teeth checked is definitely in order to rule out any issues there.
Also -- I know you said you dewormed him, which is good...what wormer did you use? I know when I first got my horse the vet recommended Strongid...it covers a variety of things but is also not the most severe dewormer, so it tends to be good for horses who have not been wormed in awhile to get them back into it without upsetting their sensitive systems.