1. Hayden Valley is a picturesque valley located in the Yellowstone National Park in Wyoming, USA. It is known for its beautiful landscapes and diverse wildlife. The valley is home to bison, elk, pronghorns, grizzly bears and other animals. Visitors can witness the animals grazing and roaming around the valley. The valley is also famous for its geothermal features, hot springs, and geysers. \"The Grand Prismatic Spring\", the largest hot spring in the park, is located just a few miles away from the valley.

2. The park is open year-round, and the best time to visit Hayden Valley is from May to September. The park opens at 8:00 am, and closing time varies according to the season. Visitors can contact the park office at +1 (307) 344-7381 for more information and details.

3. There is no ticket required to enter the Hayden Valley or any other part of Yellowstone National Park. There is a park admission fee, which is valid for seven days, and visitors can buy it online or at the park entrance. There are various transportation options available such as private cars, shuttle buses, and taxis to roam around the valley and other parts of the park.