This is my second year raising Brahmas. Last spring, I picked up three sexed pullets, and one was still a roo. Out of the ordinary for Brahma roos, he was kind of a jerk when it came to his ladies once the hormones kicked in. A nice couple who had recently lost all but one of their Brahma flock fell in love with mine while seeing me about a guinea cock late last summer, so I may never know if he aged out of raping every female bird in the yard (including the ducks). While all were big and fluffy, the hens were exceptionally submissive in flock dynamics but still easily handled (more afraid of us than I'd hoped though).
This year, I have two Light Brahmas and three Dark Brahmas, all of whom are incredibly sweet natured, fluffy and quiet. The Light Brahmas are super hard to sex and feather very slowly. They're also bad about sending out mixed signals in that one will have a comb that says it might be a boy, but have perfectly rounded feathers. One might have the stature but no comb. Stuff like that.
The Dark Brahmas are supposedly easier to sex but take for freaking ever to get feathers. Mine are about six weeks old, and I think I might know which genders they are now. They're still not well feathered. I can pick up and cuddle of the five Brahmas, pretty much anytime I want. Some of them will also seek my company out and request cuddles. They are all closer to the bottom than the top of the pecking order, but this may change as they get bigger (they're one to a few weeks growth behind the biggest birds).
***EDIT 6/8/15***
Pretty sure both Light Brahmas are hens. The three Dark Brahmas are 2 Roos and 1 Hen. The bigger LB is now dubbed Shakira because she's a big bootied Columbian gal. Despite being very low on the hierarchy, she helps my SLW break up fights between the turkeys (who all outweigh them by multiples). She is a fearsome bozen and bouncer, but is completely safe with other birds and children (so long as nobody's yelping for help). The smaller of the LB pair is super quiet and strangely small for a Brahma. The little one has a big pale comb; the big one has almost no comb still, but it's flaming red.
The Dark Brahmas are some of the sweetest birds I've ever met. Incredibly sweet natured, huge, fluffy, soft cuddle buddies. They like being held and pet [especially the boys, who are now informally dubbed "Mag the Mighty" and "Wun Wun" (recently finished the fifth book of A Song of Ice and Fire, in case you're wondering)]. Super sweet birds, and super quiet. Days go by without these birds so much as peeping. They're four months old and have never crowed. Never peck anyone or other birds, though they do take note of invaders to the yard (and stare down cats). They are the number one offenders of raiding my house at every opportunity. Any means available, these birds find to enter my house and will cheerfully peruse my floors for anything the kids may have dropped from the table. They are fiends for all things people. Hands down top birds of this year's purchases for overall temperament (and this includes the turkeys, which I love oodles).
*A sexing note on Dark Brahmas*
Once DBs feather out and get those later juvenile feathers (the "big boy" and "big girl" feathers prior to adult plumage), you can sex them by looking at them. DBs are really just silver partridge colored, so all the same sexing tricks should hold. Look for black chests and honest-to-goodness lacing patterns. Boys will get lacing on their heads, necks and saddles, but girls are laced everywhere. At first the chicks were brown and initially feathered brown as well--much like my other partridge colored birds. Some people have told me that funky mottled feathers imply this "lacing", but THAT'S NOT TRUE. You've gotta wait for bigger girl and boy feathers to show up. They can have substantial red and brown feathering even into the latest juvenile plumage. Both of my DB roos have red on their wings, though Wun Wun has a lot more (and is much larger). Some of it may be breeding or the genetics behind the silver partridge coloring, but the fact remains that many people have been told to expect something very different from what hatcheries will deliver. Expect a lot of red and brown and mottling in both genders for the first few months until the black and white big kid feathers start cropping up (they start on the head and make these chicks look super awkward for a long time).