Big enough according to what? The manufacturer? Do you have one of those cute but way too small prefabs that boast unrealistic capacity? Having a tight coop in the winter sucks... Especially if your run isn't weather proof. Chickens hate snow. They also hate strong winds, because those ruffle their feathers and break the insulating bubble of air underneath that keeps them warm. PA gets snow, and cold winters. If your chickens decide they don't want to go out for the day (or the week), what then? If they are tight, they'll fight, they'll fill the space with poop, you'll need to clean more often, and deal with bullying and potential bloodshed... A tight coop is just problems waiting to happen (I won't even get into ventilation... another common problem of tight coops). So, before winter really sets in, think about what your game plan is for bad weather, and spaces your chickens can occupy in bad weather. A very common misconception is that the coop is where the chickens "only" sleep and lay, so it can afford to be tiny. That's not true. Especially not in cold climates, where the chickens might find themselves stuck inside for extended periods of time during showstorms, or especially bad weather, or if your run isn't covered and protected, or if you just don't feel like shoveling today.