Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to cook or boil whole grains for horses [title] Decide on the type of grain. [step] There are many grains today, and only a handful can be fed to horses, these include barley and oats. There are other grains available to feed, but precautions need to be taken during the boiling and feeding.

Ending1: [substeps] Whole grains are the safest to feed horses that are past their prime. The carbohydrates in whole grains are needed during the entire process, so a horse can be quite stubborn. Ending2: If a horse is vomiting, feeding this may cause harm (or injury) or death (an unavoidable reaction). Horses are used to having their food served according to the grain's species. Ending3: They can be bought at your local tack yard. Most markets have brown and white grain that they throw in the trough or are used as snack foods. Ending4: Linseed needs special care as if it is not boiled correctly causes a build up of acid, and also the toxins (which you boil out of them) don't get removed and get into the horses body. Wheat should also not be fed at any time.

Answer format: ending1/ending2/ending3/ending4