The phrase "fresh hay" refers to recently cut or harvested grass that is used as food for animals or for bedding. It means that the hay is new, clean, and has not started to rot or decay. Full definition
First and foremost lots of fresh hay is very important, you rabbit should be eating a stack of hay almost the same size as itself each day. (bunnyproof.com)
Always provide fresh hay and fresh veggies for your pet even during travels to and from the clinic. (melbournerabbitclinic.com)
For a special snack, try mixing some rolled oats into your guinea pig's pellets or stuff a small cardboard tube with fresh hay. (humanesociety.org)