I'm brand spankin' new at this myself and have had my first flock of 25 (16 Barred Rocks and 9 Leghorns) for two weeks tomorrow. I made the brooder and coop/run about 200% bigger than what I originally estimated I'd need since I figured you could always reduce space if need be but making it bigger is a lot tougher, and I'm glad I did. My brooder is a repurposed play set and is 7'X4' but the gals seem happy in it. They've been stretching out quite a bit and practicing flying around which they wouldn't have been able to do in a small brooder. So far I haven't had any problems (knock-knock) and I attribute some of that to low stress due to having enough room. I'm still working on my run but my 8'X8' coop is done and the 8'X24' run should be done in another week or so. The gals seem really used to me and my wife and I think it's because we go out in the garage where the brooder is at and talk to them a lot. They'll take chick feed right out of our hands and greet us when we walk in. I've read a lot about leghorn's being flighty but only some of mine are; most are just as friendly and curious as the Barred Rocks. I'm having a whole lot of fun with this and had no idea it would be so enjoyable. I'm even thinking about possibly getting ducks and turkeys too. I've always been heavy into vegetable gardening and hobby farm stuff but now I feel like I have a complete setup with the birds. I can see doing this for the rest of my days - it's a real blast!
you have a 64 sq. ft. coop with 25 chickens as a min. they should have about 4 sq. ft. per bird inside the coop yours only has 2.56 and a min. for a run is 10sq. ft. per bird you have 7.68, and barred rocks aren't huge birds but they have some size to them too squished of quarters leads to picking so you might want to keep an eye on your chickens.