Like centrachild, I hold off on scratch until later, at least 5 weeks old. The only "treats" they get, are grass and bugs that they get when I start putting them outside. Which brings us to your other question, and where I differ from your first reply. We have a small grassy area that gets direct sun, with a section of shade provided. After the first few days, once I know they are all eating and drinking and there are no visible problems, I'll take them outside at an hour or two at a time, even at 70ish degrees. Not on cloudy days at that temperature, but when it's sunny, it seems like enough. Your best barometer is the chicks themselves. When you first put them out, they will be chirping, because it's all new to them. But watch them...if they begin to settle down, and start to spread out pecking and exploring, they are fine. Just keep listening, and if they get too cold, they will tell you.
I don't even go 95 in the brooder anymore. Hot spot at 90 for the first 3 days, and then that light gets raised. I've had much better results since I started cooling things down a bit earlier, a trick I learned from an old chicken farmer. By week 3, mine are outside in a small coop open on one side, with temps in the mid 50's to low 60's. I have 3 week old chicks outside right now, and was in the mid 40's last night. They huddled and were quite fine today. Of course, if you have any that are having issues, you'll want to keep them warmer for longer.
