yea emu's when scared WILL ......and try.....to fit...jump...anything they can to escape... a 10 inch gap is a pretty big gap! i would put a strip of field fencing .....some how to block the gap! my emus are REALLY calm i always joke that i got broken emus they never play or run but when they get scared.....look out! i have 5 feet as the MAIN pen and they are only 9 months old...and they almost got OVER!! now there in a small winter part connected to our barn with 6 feet dog kennels lol but we are planning new pens for future birds were getting this winter ......thats why we will NEVER keep trios to not have the risk of jumpers!