My crazy horses will eat anything they see us eat, which has included banana's, toast with jelly, watermelon, apples, carrots, love pears, sweetcorn, oatmeal cookies, peanut butter cookies, muffins any kind, I make them there own sometimes. They also try to drink my coffee, if they can turn my cup over.
Whatever you try do be careful a horses diet should be 90% or better roughage,/Hay/Alfalfa/grass. Horses can not survive on treats, they also need an adjustment time when playing with there feed you got lucky no one got a belly ache or worse with the turnips. Always have an extra few bales of hay around when a storm is approaching, it may save your horses lives, I always watch to see when the weather is taking a turn for the worse and count bales to make sure I have plenty just in case of an emergency...... if need be I will run to get more if I think I might need it.
Horses are meant by nature to eat almost 24/7/365, their system requires large amounts of forage to digest to make heat and turn into energy, and growth. Quick changes in their feed start a cycle that is not good for them, their stomach make acid 24 hours a day, if they go too long without food or eat the wrong food, they could easily colic and die.
Keep treats to a minimum and feed hay/grass as their main stay diet. every 6 hours if that's possible, I feed mine 4 times a day, 5 in the winter when they need extra forage for heat. Plus their pellets which are not grain vit. minerals, and alfalfa, horses don't need grain it really isn't good for them. Kim