We have started a project to assemble collections of photos to help people trying to sex their chicks. What we are aiming for, for each breed included in this project, is a collection of photos showing chicks of both genders at as wide a variety of ages as possible, up to an age where differences between male and female are obvious. Such a resource will allow people to see at a glance how old their chicks should be before they have a go at discriminating males from females. For most breeds, it should be possible to use such a collection of photos to either confirm or dismiss previously suggested diagnostic features, and it may even be possible to identify new features to help pick out birds of one gender or the other.
The most valuable photos will be those that show the same chicks at a variety of different ages, ranging from before to after their gender is apparent from the photos. Moreover, these photos should clearly show those features that are most useful for discriminating the gender of the relevant breed. Such series of photos are not nearly as easy to find on the internet as one might think! If you already have such a series of photos that you'd be willing to share, that's great. If you don't, but are currently (or shortly to be) raising chicks, please consider taking regular photos of them as they grow older, until they are old enough that their gender is clear. If you have a run of more than one chick of a particular breed, such a series of photos could be particularly useful, but of course you should make sure that the identity of individual chicks can be tracked through the series. In many cases this will be possible due to individual markings of the chicks, but if the chicks are sufficiently similar it may be useful to mark them yourself in some way (e.g. by loosely tying coloured ribbon or thread around their legs), or by putting a spot of waterproof marker pen on their beak.
Anyone interested in contributing to this project should get in touch with me. Together with Rob (aka Nifty-Chicken) I have set up a very rudimentary prototype showing roughly what form the resource could take (for just a couple of breeds) here:
I'm tinkering away with this, but Rob and I are hoping that soon this project will get to a point where it will be possible for contributors to add photos themselves. However, we're not quite there yet, and until then, it would be really helpful if you could make yourselves (and the breeds you are interested in) known to us (so we can contact you when the resource is ready) and start assembling series of photos of chicks of known age and (initially) unknown genders. Also, spread the word the more people contribute to this resource the more helpful it will be. The breeds that we cover will be determined by the breeds that people show an interest in, but basically any breed that can't be sexed straight after hatching would be suitable for inclusion.
Thanks in advance for your interest!