How long before having the kittens does the queen produce milk?

To answer you question, milk will show up in her teats 3 to 5 days before labor, 24 hours before labor you can see leakage or express milk from her teats, please do not try this, I am sure she would not like you trying every day until she goes into labor.

I do not want to sound rude but did you read any of the articles researched for you from www.peteducation.com every thing you need to know is in there.