X 2..... as long as they have access to get back to their heat Source when needed, anywhere after about 5 days is when I start letting my little ones start exploring larger spaces. I start by allowing them access to gradually larger spaces so that they learn to return to that heat source reliably as needed and work up to bigger spaces over a course of a few days. It's a little trickier than having chicks being with a Broody hen because in that situation the heat source, the hen, actually travels with them and they don't have to remember how to get back to it as much as they do with a fixed heat Source like a heat plate or heat pad in their brooder. For me, I start with a few hours in the afternoon after the hens have all laid and I can walk them out of the coop and I open the little hatch door so that they can move from the brooder space into the coop itself. I watch and see that they return to the heat source as needed, and if I notice anybody struggling to find it or looking chilled and not returning to it I will move them over to it so that they learn that habit. I don't have the ability to create a dedicated run space for them attached to how my incoop brooder space is.... but by 2/3 weeks they are venturing into the big run during their out time, I just have to time it so that I can exclude the hens from the entire space for however long I want to let the chicks explore. This also is the time where I start training them to go from the run back into the coop, another lesson a mother hen would be teaching them but in the absence of that it's our job. They also start mingling with the adults at 3ish weeks ( sometimes a little earlier sometimes a little later, depends on the adults I have at the time and my read for how they are adjusting to the chicks through the barriers). By 5/6 weeks the chicks are completely integrated into the flock, in the habit of moving back and forth between run and coop and also ranging in the larger fenced yard during the day.
