4HDad - I would like to comment about your cockerel. For starters, let me just say that you do not find birds that have as good of conformation as that Self Blue cockerel very often. Second off, that boy is backed up with some nice color. Impressive.
Let me start with his head and I'll work my way to the tail.
Comb: A bit rough and the base is a bit high. Also, there is a blade shaped spike that does not follow the contour of the head. He does have rounded points on the comb, but ideally they should be "fine, small, tooth-shaped, rounded points". We are talking no more than 4mm in height or width. This is why I say the comb is a bit rough because those rounded points are a bit on the large side. Also, there appears to be a slight hollowed out portion of the comb on the back end of it. I say the comb is a bit high because a d'Anver is supposed to have a wedge shaped comb of helmet fit. This means that the point of attachment should never be visible. If it is, it means your comb is not following the contour of the head close enough. The start of the comb is a bit narrow, but I am being picky now. The comb is my biggest critique on your bird. It is also the easiest to fix through breeding and it is not worth very many points in the show room. So, no worries.
Eyes: Round, bright, healthy AND the proper color.
Face: Can't really see much of it - so great! Looks red and healthy and free of wrinkles, folds and bristles.
Wattles: Very small, almost non-existant, which is exactly what you want.
Skull: Looks broad. Well developed. The brow is well furnished with feathers.
Beak: Medium in length, strong, curved.
Beard and Muffs: A bit shallow in the beard and there is not the best definition between the beard and muffs, but again, this is usually an easy fix through breeding. I would say they are on the small side of the average, but certainly better than some others I have seen.
Neck: Well developed for a cockerel! In the top picture he is holding his head a bit high, but you can see a convex curvature of the hackles that suggests he really is going to be developing a bull neck. This is fantastic! His neck in the last picture is being held where it should be height wise, but I can not tell how far back he holds it. In traditional Belgian type it should be held well back from the breast. It looks like he might carry it a bit forward though. The hackles do not meet in the front of the neck though, so there is a bit more work that can be done in the hackle department. Not many d'Anvers exhibit that trait anyway.
Back: Very short and very broad, you can tell its breadth through the last photo with your boy facing the camera. He has a nice, thick and cobby body. Also, if he was holding his head down and back in the top picture like he is in the lower pictures, I imagine some of those hackle feathers touch the base of the tail, which is exactly what most Belgian standards call for (I think this was left out in the American standard). You can tell his back slants to his tail because his breast is carried a bit higher than the base of the tail, which is perfect. The back is worth a lot of points in the standard and it says a lot about the quality of this bird.
Breast: Well filled out, carried proudly, good.
Wings: Large and slung low as to cover the thighs and the upper legs - beautiful! The American standard only specifies "slanting towards hocks" or something rather nondescript such as that. If you really get into Belgian history though and discuss type with overseas breeders, you find that the wings really should be low - just a hair from touching the ground! Keep in mind that they should not be perfectly perpendicular or carried before the legs, that is just awkward. Your boy carries them well. You can tell that this is his natural wing carriage too because posterior border of the wing is right next to the saddle. In males carrying their wings artificially low relative to their normal stance, you will see a gap containing under-feathers between the saddle and the wing border. The fact that this is the natural carriage of your cockerel is impressive.
Legs and Thighs: Well set apart - legs are the length they should be. They say you can tell if a bird has the proper leg length by looking at their profile - the near foot should be just visible beyond the low-slung wing. Your bird fits this description to a T! Again, most d'Anvers have legs that are too long. My only concern is the fact that your bird looks a bit bow-legged in the last photo. I assumed it was just the way he was standing. Either way, both his middle toes point a bit inward and the one leg is sitting a bit funny. It's probably just a fluke though.
Saddle and Tail Coverts: Short, carried well up the tail but not profuse enough to obscure the tail. As it should be. The Self Blue gene makes this area seem a bit rough, but you really can not get around that in this variety.
Main Sickles: Short, barely curved and extending just beyond the main tail. This is precisely how they are supposed to look. They are supposed to have a distinct point at the end, but again the Self Blue gene makes this difficult to achieve.
Tail: I would say the tail carriage is actually a bit low. He looks like he carries his tail at about 50 degrees above the horizontal. Standard calls for 75 degrees. But, this is not necessarily a bad thing. For breeding this is a very good thing, as most d'Anvers carry their tail higher with age and it is nice to have a sire that helps prevent squirrel tailed offspring. It's always good to start a bit on the low side. The main tail is well spread and the gaps between the feathers are minimal. There is some funny business going on with the lower feathers near the bottom, looks like one of the lower feathers is longer than it should be, but he is a cockerel and this is probably something that will sort itself out with the yearling molt.
Overall Assessment: Hang on to this bird, he is a jewel. Whoever bred him has a good idea of what a Belgian d'Anver is supposed to look like and did a very nice job of bringing that type to reality.
Color: Ah yes, and his color is good too - I did not see cream lacing, brownish tingr or the usual inconsistencies you see in Self Blues. There are some stress marks on the feathers, but this is very very common when you get a high quality, clear Self Blue. Seems like the better the Self Blue color you get, the more stress marks and shredded edges you get. Just some of the hazards of the variety I guess.