Welcome to the wonderful world of chickens! Oh, and Welcome to BYC alsoyes, he is a boyI was just posting some pictures of the ones that would let me take them today. They are all at least 4 - 4 1/2 months old. So, you can tell by the girl's combs that they are ready to lay soon? I have so much to learn!
When a hen approaches laying age their combs (and wattles if they have any) will get brighter red. The boys' combs will turn before that, as their hormones kick in, but the girls won't change until they are approaching POL (Point Of Lay). Another sign is that they will "squat" for the boys (or for you), crouch down on the ground. Then there is the nesting fun, scratching all the padding out of the boxes and throwing it over their heads. And then the "I'm upset" song also known as the "egg song" on BYC - some hens get upset when they lay an egg, some get upset when somebody else kicks them out of the nest - and once one starts it the whole bunch can join in and make a chorus!
New hens will also sometimes not lay in the nest - you may find eggs in odd places, including broken ones under the roost because they laid while sitting on the roost! To encourage using the nesting boxes I use golf balls or fake eggs (I like the rock ones, pretty colors). Put a few in the nest and that will tell them "It's safe to lay here, look at all the other eggs that are safe here."
From the color of the first pictured girl's comb I would say she is the closest - and may even be responsible for that egg. You can check their vent (back hole) and see - those that are moist and pink looking are laying, those that are dry and white looking are not.
