I checked on my five chicks today and there were only four, he could have gotten out of the run somehow and got eaten by a hawk because I dont know where else he could be.
Well I helped him hatch so it is very sad and he was my only leghorn chick which is sad too, but I do have four other lovely silkie chicks and another six chicks in the bator. Maybe he will turn up, but until then my fingers are crossed.