One more clue is that there are no nubs of developing spurs that a tom would have. If it isn't too much trouble, hold it so it is laying on its back in your lap and see what the leg reaction is. If it brings its legs up to its chest and holds them there, it is very likely a hen. If it keeps its legs kicking or holds one or both to the back or straight up, that would be an indication that it is a tom.
Just my preference but I breed a self blue (Lavender) tom to Blue Slate hens to avoid getting black poults.
Good luck.
Well, here was the result. Could barely get 'em on it's back. But when I did, still lots of struggling and pulled them in briefly. After that, it kept it's legs extended,flailing like it were biking and kept them out.
Side note, it makes a sound when foraging, something I would familiarize with a rooster who found food for hens... if that makes sense.