Do I need more than one Hub?Updated 5 months ago

Maybe. Each Hub can connect up to 100 Trackers, so if all your cats spend time together in a common area, e.g. the kitchen, for mealtimes, you'll be OK with one Hub. 
Consider additional Hubs to cover all spaces for large properties or if your cats are often in different areas, especially if they are over 10 meters apart (the range for Tracker and Hub connectivity). Generally, it's like a wifi repeater - if you need more than one, you'll probably need the extra Hub(s) too.