Yes. Horses generally don't know when to stop eating and can die from overeating.
Daffodils can be harmful to a horse, if too much is eaten.
A bit, but the acid isn't too good for it, so not too much. Most horses don't like them though.
Any breed can eat grass, many breeds tho r more suseptable to colic or laminitis from eating too much grass. Especially spring grass that has the most nutrients at the roots and the early spring grass as it grow is easy for a horse to eat too much.
any horse can eat too many apples small or large if they do they will get really sick or they will get colic
if it lives out, let it eat as much as it likes GET A HORSE MANUEL
It depends on the horse. If your horse is fat then you need to cut down on the horse feed, but if your horse is too skinny then you need to increase their feed until the horse gets back up to his/her weight.
Horses have very small stomachs so they eat little and often. If you feed a horse too much too quickly they may collic. In the wild a horse will graze as much as 16 hours a day. They also enjoy a variety of foods. Although their main source of foods are grasses they will also eat flowers, berries, fruit and nuts if they want.
You can eat too much of anything.
Horses can get quite Obese depending on what they are fed and their activity level. No horse should be allowed to get overweight, it is in fact worse for a horse to be too fat rather than too thin. But the best thing is for a horse to be fit and healthy.
A horse that eats a lot
If the cougar had someone to help cut the horse up, refrigerate the parts, and serve them up in day-sized meals, then sure. By it self - no. An adult horse is a too big prey for a cougar to tackle, and much of the horse would spoil or rot before the cougar would be able to eat it.
No snake will eat a horse. They are too big and too heavy. But if it is a full grown anaconda or burimese python, it might eat a newborn horse if found astray. I hope this is helpful and good luck.