Question: underdevloped-no chest-hip bones sticking out-been trying to put weight-not doing greato that respect-need advise-no pasture but small turnout-stalled at night-gait
problems are:
no head nod-i think we are racking in that it is a smooth gait.
Tries cavelettis and all he want to do is either jump them and hit them with his back feet. Will not trot over them but wants to canter over them.
Also have a head set problem-a little nosy 

Thank you

The lack of muscle and other physical development issues can best be dealt with through a consultation with a veterinarian.  I would suspect teeth, parasites, and diet all need some attention.

A horse that is supposed to be doing a running walk and is not nodding his head is often not doing a running walk, as you have suspected.  However, some of them do walk with little head nod.  How does the horse feel under your seat?  Is there a feeling of  "hula" going on with the hind legs,or do you feel more of a push to the front in the saddle?  If you are feeling the "hula" effect, the horse is most likely racking.  To help a horse that is
racking start walking, you will probably have some success by asking the horse to relax and lower his head by lowering your hands to either side of his withers ( more of a hunt position than a saddle seat one) and sitting more to the center of the saddle, heels under hips, hips under shoulders, not in a chair type seat.

I am not sure what you want to accomplish with cavallettis.  If this is a gaited horse, one that racks or running walks, what is your goal by trying to get him to trot over them?  They may be  a helpful tool for longe work with a horse's pace problem, but for riding one that is more square in his gait, they are not necessary.  In any case, if you use them as a tool,  they should be set low, and spaced for the horse that is working over them, so that he goes over them in the best place in his stride and does not hit them.  Try first with one, set about 6 inches off the ground, then add a second, no closer than 6 feet to the first (depending on the length of steps of the horse) if you are planning to continue this sort of work.  work him over them at no faster than an ordinary walk until he is comfortable with
them.

The horse's head carriage is a result of the use of the rider's hands and the bit.  Are you in a true, non shanked, snaffle or a broken mouth bit with shanks?  If the latter, it can contribute to a nose out problem.  If the former, if you ride with high hands and steady tension, this can also contribute to a nose out.  Ideally, the nose comes in as the horse relaxes his jaw on the bit and starts to work through his body. To ask the horse to
bring the nose in, push him with leg pressure into the snaffle bit, with your hands lowered,  fixed (not pulling back or yielding forward) with light vibrations on the reins.  This may also result in the running walk, as mentioned above.

Good luck.

Lee Ziegler