i agree with mericox.
i knwo if id done this with the wowies id have such picky eaters.
cocciddia can make a dog go off its food as can the medication.
also depending on the breed he may not eat alot normally...people are amazed by how LITTLE food my dogs actually eat, i have to remind them how TINY my dogs stomachs are so keep this in mind.
you could try a different brand of food...without knowing what hes eating now its hard to say.
MOST dogs wont starve themselves and once hungry enough will actually eat...
try leaving his food down to pick at at his whim for now...mabe hes used to having food down all the time.
my wowies wont eat an actual MEAL, instead the dry is down for them to take as they want, ive found this the ONLY way to get them to eat dry food...it makes potty training harder as theres no schedual to judge...but at least they eat.
its only if ive got an incredibly picky eater thats obviously loosing strength ect that i will start using additives, and then ill start by simply moistening the dry food before adding anything extra.
as for the crying...
be persistent, dont reward him when he cries, instead wait till hes quiet and then go in and give him a treat/love.
remember, this little guy has been taken away from his mother, his litter mates his people his home and everything hes used to and placed into a new place with new things to see, new smells, new people to get used to...its frightening.
a couple of suggestions that worked for jasper (who was a banchee when he first came home too)
move the crate/his bed next to your bed, when he squeeks, put a hand down and assure him all is ok, but do not take him out/pick him up. doing so will just mean crying = someone comes and gets me...
instead again assure him calmly tell him its bedtime and go back to sleep. if he continues to cry take him out to go potty and then straight back to his bed...he'll quickly learn that crying when crated/in bed means "i have to pee" but nothing else...once hes sleeping through the night slowly start moving the crate/bad further away from your own.
also it might be worth buying a couple of peices of fleece, cut about 1/2 yard and then cut in 1/2 lenghtways makes a perfect crate blanket, sleep with one while the others in his bed...this way hes always got something that smells like you...
and during the day id agree with bullmastifmamma, try and start it slowly, ease him into being aloe gently, start with just leaving him alone in his "room" for a few seconds, literally, close the door and then imediatly reopen it before giving him time to cry...
when you leave or reeneter a room dont make a huge fuss or show about it, be calm direct and just do it...saying "oh bye bye" or coddling the puppy will make him think he has reason to be worried your leaving. when you come back in the room be calm, wait till he relaxes then reward...
once youve done this a few times with sucessfull quietness, increase the time the door is closed...literally only by a few seconds, you dont want to give him time to cry...
over time increase...
i know that folks work and you cant do this all the time, but practicing this during the time you are home will help assure him that you will come back. leave him with a blanket that smells like you and busy toys like a kong filled with kibble and the hole sealed with a good layer of low salt peanut butter...