Out walking after work this afternoon and saw someone with some young children feeding a horse in a field leaves and various crap picked off the ground.
I’ve hear stories of people who’ve dumped grass clippings on the ground horses have eaten these and got colic.
My previous horse was a blimp and was on strip grazing/already grazed down fields and I once caught someone feeding him slices of bread 
Please don’t do it, horses can’t vomit and get very ill if something doesn’t agree with them.