[Eddie]

Thank you both for your replies. I have been opening it up briefly everyday or so.

My concern is we are also going on holiday for two weeks. Thankfully they will still only be around 49 days old when we get back. My mother in law has also offered to pop in and check on the eggs whilst away.

I don't expect any to hatch and was getting her to pop in to check humidity, top up water and let air in. We don't live that close so was only going to get her to pop in a few times during the two weeks.

Hence my worry about oxygen levels, how often can you leave it without opening it up?