The windmill (at the farm)
The windmill at the farm gives you a visual indication of how many population slots you’ve filled with troops:

No sails = No troops recruited at your city (all population slots are free)

Turning windmill = You’ve recruited some troops, but there are still population slots left (so you can recruit more)

Stationary windmill = You’ve used up all population slots at the farm, your army is at maximum size.
You can still activate militia at the farm even if you have 0 population slots left.
If you need extra population slots, research “Plow” at the Academy, or build a Thermal Baths (requires farm level 35 or above) in the left special building slot.
Militia Officer Busted At Border With Biotoxin Guide, Bomb Recipes
by David Holthouse | mediamatters.org
Federal prosecutors in Alaska filed a motion Friday to deny bail to an officer of the Alaska Peacemaker Militia, a right-wing extremist sovereign citizens group, after she attempted to enter Canada in late October through a remote Yukon Territory border crossing.
Mary Ann Morgan, 53, was driving a truck containing virtually no personal effects but what prosecutors termed a “horde of documents” including detailed information on home-cooked explosives and ricin, an extremely lethal toxin derived from castor beans and weaponized using lye or solvent.
Prosecutors cited the fact that last week, four members of a militia group in Georgia were arrested for allegedly plotting to attack various government targets using ricin and explosives and said Morgan poses “risk to the public in general, law enforcement or the judiciary.”
Also in the Chevy S-10 pick-up truck driven by Morgan was a .32 caliber Beretta handgun that Morgan, a convicted felon, is prohibited from possessing. Morgan was convicted in 2001 of Custodial Interference in the First Degree for violating a child custody agreement. Canadian law also bans private U.S. citizens from driving handguns across the border, and strictly prohibits the possession anywhere in Canada of easily concealable handguns including .32 caliber semi-automatics.
After discovering the handgun, Canadian Border Security Agency officers turned custody of Morgan over to the U.S. Customs and Border Protection and Alaska State Troopers. Morgan told Canadian border guards she was headed for a meeting about the U.S. Constitution being held in Montana, according to Canadian law enforcement sources in the Yukon Territory.
The motion identifies Morgan as secretary of the sovereign citizen Alaska Peacemaker Militia, part of a movement rooted in racism, anti-government extremism and bizarre conspiracy theories that is growing nationwide as part of an ongoing surge in right-wing militia activity.