Hey,
Welcome to chicken keeping!
Agree with others with one addition:
I would say the risk isworth it, becuase the alternative seems to be keeping then hens in a very small space. We generaly recomend 2msq per bird, so by that note you have twice as many brids as you should for the size of run.
If you are worried, get some pond netting (very cheap) i think £5 for a reel from Bnq, and just chuck it over the top of your electric fence area.
I would let them out into it though
Lew