selective paedomorphosis

["Pat Grant (Library: Serials Catalog" <PATG@vax2.concordia.ca>]

Sorry gang, I'm  having trouble with the idea of massive legs and tiny
snouts as paedmorphic traits in avians/non-avian theropods/whatever. 
>From what (little, admittedly) I've seen of hatchlings, etc., the head
is HUGE (which seems very far indeed from the case in ratites), the
beak is small only in proportion to that head.  In altricial
hatchlings, the legs may be too puny to do more than prop up the body
for the first couple of days after hatching, and hardly sufficient to
do even that at first.  Obviously, an animal with no means of
locomotion wouldn't last long once its parents kicked it out (=would
be selected against), but where did that big head go?  If neoteny is
being proposed as a *suite* of characters which provides the only
viable route to flightlessness, how much leeway is there in choosing what
characters are to be accorded a place in this suite?  If Nature gets to
pick and choose among available neotenic characters, why not admit the
other usual evolutionary mechanisms as well?  "It's the mechanism
that best explains what flightless birds we have now" is presumably
testable, given the finite number of eligible species and the amount
of evidence that could be amassed for each; claiming it as the ONLY
mechanism, even for finite numbers of known species, has a strong
whiff of negative evidence about it; extending it back to the Mezozoic
sounds dubious indeed. 

Pat