30 birds would be a lot.
In general, you are pretty much maxed out on the coop size.......right at 4 SF per bird.......and as long as it was built right and setup right (meaning enough sunlight and ventilation), they may and could ride out some rough patches of winter.....staying inside for long stretches of time, which depending on how the run was setup, they may want to do. If the run was setup to block north winds and give them covered space open to the south and the winter sun, they would probably use that a lot.
Your run space is 26 SF per bird. That is more than than is typically used, but here is the rub. They will strip that bare and "fowl" it in no time. To give them a fair shot at anything that resembles green poultry pasture would mean a half acre or more........and to make a run that size would be expensive. So.....probably leave the run the size it is now, with plans to make it a useable playpen in winter. That is likely going to mean adding a lot of litter and bedding to keep it clean and sanitary looking.
To stretch that, instead of more "run" space, you could contemplate building a "chicken yard", which is essentially an expanded fenced in area (or free range them if that works for you with predators, etc). Confinement fence.....especially if it is electric fence.......is going to be much less expensive than an expanded run, and likely will accomplish what you want it to do. Kinda depends on how much room you have to work with and how you want to keep your birds.
But 30 birds are a lot.
