Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to give your horse the right supplements [title] Collect a sample of the hay you feed your horse. [step] Most horses eat a combination of roughage, or hay, and concentrates, or grain products. Usually, nutritional content will be listed on the grain feed label, so you'll only need to collect a sample of your hay to be tested.

Ending1: [title] Contact an agricultural research laboratory to have your hay tested. [step] Agricultural research laboratories offer hay testing that will provide you information about the crude protein content, fiber, and vitamins and minerals in your feed. Ending2: [substeps] In addition to your regular hay, your horse should have hay that is rich in protein, which is good for the horse's digestive system. When buying a sugar supplement, you should pay attention to the amount of sugar in the supplement. Ending3: Take your sample from all source : [substeps] The poop from the hay you feed your horse oats from the hay packaging materials etc. A sample of the hay was fed to your horse, this differs by horse. Ending4: [substeps] Keep the portion of the hay you collect clear, or just below the standard fogging range. Take no more than one' tube'.

Answer format: ending1/ending2/ending3/ending4