I recently (locally) purchased some BCM hatching eggs from a novice chicken farmer. He kept his hatching eggs small side up instead of down and I didn't notice this mistake until I was home... I am guessing they were like that close to a week, possibly a little longer. Will they still be fertile or will the air sac be too compromised?
You'll have to candle the eggs and see where they air sac is. It is possible to hatch eggs with compromised air sacs, though it's tricky. Have a look through this article, there are some links to managing damaged airs acs: https://www.backyardchickens.com/a/hatching-eggs-101
