Much would depend on the weather I would think, I let my chicks outside to play from the first day I had them, they were 4 days old, and nine days old. But... here in Tucson, our days are still in the high 80s and low 90's. There is no danger of them getting too cold around here!! And I have a secure place for them to play where they can't get eaten or hurt.
Congrats on your new chicks... where are those pictures?
at what age can chicks go out side?
Also when can they go on growers?
Chicks start out with their heat at 95 degrees, it is then lowered by 5 degrees each week until it's about 70 degrees or until they are fully feathered. If it's in the 80s outside during the day right now, then you could take them out for an hour or so each day. Night times are when they are more likely to be too cold. Just keep a close eye on them all the time... if they are all huddled together (especially under the heat lamp) then they are too cold. If they are all around the edges of the brooder (away from the heat lamp), then they are too hot. There should be some under the lamp, around the edges and wandering around.
If you have them on starter right now you can switch them to grower around 9 to 12 weeks old. Some people can't get starter and use starter/grower - you keep them on that until they are laying age (usually about 20 weeks old) or they lay their first egg; then you switch them to layer feed.