A Barn is a building to house Feedgroups in FeedView. You are able to give a Barn any name you like. If you have multiple locations you may want to name your barns as follows: Farm Name - Barn Name. This will allow you to keep track of them easier. If your Barns have unique identifiers already this won't be necessary.
Barns have FeedBins attached to them, which store the feed to be fed to a Feedgroup.
If you have rooms in your barn it is recommended to create a Barn for each room.