I am a newbie and posted this sex suggestion for guinea that has always worked for me since I was little.
Female guinea nostral slants will be narrow as if almost closed and males will be open more. Never mis-sexed this way. Feed store called to have me sex until I gave them secret. Now they are able to sell pairs!
Also, I do leave mine up for 10 weeks and all of my guinea prefer Chan my roo for protection rather than staying with chickens. I currently have 2 lavendars and unlike the other guineas we have had, they come back every night. I only hear noise from them when someone or something on property or if they have light projected on them at night. French Guineas on the other hand, imo, I never could get them to acclimate to a night time safe place and even after penning them for 10 weeks, they hop fence, sit by rd and wait for logger trucks then just walk out in front! Splat. We went through 3 pairs before I switched to Lavendars. Also, we always hold our guineas up in cage until she lays an egg. Otherwise, they will travel from a farm to lay so nobody can tell where eggs are. Approximately 28 days later, it is possible to see an army from 30-100 guineas approaching the feeder as they make their way back home! Lol