Remember that birds have air sacs, so choose your injection sites wisely or you might accidentally inject into one of them
Another picture:
http://chickscope.beckman.uiuc.edu/explore/embryology/day15/how.html
Picture of air sacs.
From: http://www.peteducation.com/article.cfm?c=15+1829&aid=2721
http://www.thewildclassroom.com/biodiversity/birds/aviantopics/environmentalphysiology.html
Another picture:
http://chickscope.beckman.uiuc.edu/explore/embryology/day15/how.html
Picture of air sacs.
From: http://www.peteducation.com/article.cfm?c=15+1829&aid=2721
http://www.thewildclassroom.com/biodiversity/birds/aviantopics/environmentalphysiology.html