PLEASE DO NOT FEED YOUR HORSE COOKING APPLES! good question many people dont bother to ask but yes they can cause colic I know of 2 cases so just please be careful hope this helps but yes wouldnt risk it
every year my horses have the brambly windfalls and love them.my shetland is 26 .i chuck a bucketful in the field in the morning for them to find and they have a couple more in their feed at night.
I don't feed my horses lots of apples, but if I am making an apple pie, they get the peelings and cores of the cooking apples and none of them have died yet. Would I give them several apples in one hit. No.