There are many ... why it is important to have a hobby

Hobbies give you an opportunity to enhance your life. Hobbies allow you to destress yourself while remaining mentally productive. Having hobbies promotes better health and may lower the risk of having high blood pressure. Enjoying a few hours of your hobby a week can also reduce the risk of depression and dementia.

c. to depict the cunningness of the federal soldiers

well stockyards mean a large yard containing pens and sheds, typically adjacent to a slaughterhouse, in which livestock is kept and sorted. and i'm assuming that by party you   mean a large group of people which does make sense because chicago is a very crowded place much like new york. stockyards tend to take up a lot of room due to needing the area for pens to keep animals in and the fact that stockyards are usually right by slaughterhouse where they process and distribute the product. so its much like a zoo but with some dead animal products close by.