WoWDB

List of all 27 spawn points:

/way Borean Tundra 48 8
/way Borean Tundra 81 48
/way Borean Tundra 32 60
/way Sholazar Basin 58.5 22.0
/way Sholazar Basin 36.8 19.4
/way Sholazar Basin 44.47, 69.59
/way Icecrown 47.9 86.6
/way Icecrown 73.8 64.5
/way Icecrown 43 33
/way Storm Peaks 42.5 78.5
/way Storm Peaks 65 41
/way Storm Peaks 28 52
/way Zul'Drak 75 22
/way Zul'Drak 24 63
/way Zul'Drak 57.0 39.8
/way Grizzly Hills 61 19
/way Grizzly Hills 26, 57
/way Grizzly Hills 79.60 50.79
/way Crystalsong Forest 68 49
/way Crystalsong Forest 43 43
/way Crystalsong Forest 18 57
/way Dragonblight 82 66
/way Dragonblight 64.4 43.7
/way Dragonblight 27 52
/way Howling Fjord 68.10 67.63
/way Howling Fjord 45 43
/way Howling Fjord 71.91 43.39

Credit to Astarin@Wyrmrest Accord over on the Battle.net forums for the list!

"Known locations for Unborn Val'kyr" http://us.battle.net/wow/en/forum/topic/8891689143 

Apparently, CRZ and quest phasing may interfere with the ability to see spawns and other players camping those spawn points.

According to a podcast interview with Cory Stockton over at GameDiplomat.com, the location and spawn time of catching this pet will affect the location and time of the next one. (Source)