Remember back in the winter I posted Penelope and Mr P having a crowing contest?! She could crow as well as he could!So, what I can see says pullet.
Is there a way you can get a good tail shot of each? (profile is good - but need to see the 'saddle feathers' (ones that fall on either side of the primary tail feathers) and the tail feathers themselves - including tips.
My 5+ almost 6 week old chicks - 3 are definitely pullets, one is definitely a roo, and one is questionable. (Some hens will have 1 or 2 tail feathers that curve a bit at the tip - which is also how a young rooster's tail/flag feathers start out in their first baby molt (2nd set of feathers - before a true juvenile molt) I know others can tell by the hackle feathers, but this early, I find frequently there isn't enough difference to use those.
That said, are you sure it wasn't one of the adults attempting a crow? remember what Aurora's crow sounded like. You could tell it was a crow, but it wasn't like an adult roo crow. (I have yet to have a hen crow....but I think it is less likely when you have roosters than when you don't.)
So glad I got rid of the roosts and put in the ledge - they are much happier I feel. Less bed time drama.