Never too late, LOL! Actually, it depends on how long you want them in the house and where they will go after that, since the weather is turning much cooler. Some people hatch year round.
For the last 2/3 years in a row I had chicks in the house every day of the year. and eggs euther under a hen or in the incubator. IT GOT WAY OUT OF HAND - I was hooked and had to kick myself in the butt to stop, it was hard but I only hatched one batch of chicks this spring. A mixture of my eggs and others,
Now I am hatching my secound batch of chicks from my top show winners and the hens that I think are getting to old and either may stop laying or not make it threw this harsh winter so I do not loose thier bloodlines. THEN I will hatch out another batch on Feb 14th.
I guess the answer is GO FOR IT if you can manage them.
I've got eggs in the incubator right now. I may kick myself later when cold weather really hits. I've never hatched this late in the year, so we'll see how it turns out. I figure tho they'll be ready to lay when the nice warm spring weather comes ...IF it's not like my last hatch...only 2 pullets!!!!