Please choose the correct ending to complete the given sentence: Home and Garden: [header] How to keep birds out of a barn [title] Keep your grain in bird-proof containers. [step] If birds have easy access to your grain, they'll associate your barn with food and keep coming back. To prevent that from happening, store your grain in bird-proof containers so birds can't get to it.

Ending1: [substeps] Large garbage bins with lids and sealable plastic containers are good bird-proof options for storing your grain. [title] Use covered feeders to feed your barn animals. Ending2: [substeps] If you have pigeon droppings in your milk cartons, don't dump them in your barn. Birds will see these as food; however, they won't naturally pick up droppings. Ending3: [substeps] Make sure your containers never exceed three inches or less in height. You don't want birds hitting the grain's surface. Ending4: [substeps] Choose wooden, plastic, and polyurethane containers so birds can't use them on trees and bushes. The container should have holes in the bottom to let sunlight in.

Answer format: ending1/ending2/ending3/ending4