Not that I know off. (The lack of such means it would be inappropriate to assume these are of any consequence.) What is know is that having a birthday in the last 3 months of the year means you are significantly less likely to play in the NHL then if you were born in the first 3 months. NHL players with a Jan birth month are ~60 more common than those with a Dec birth month. The likely reason for this is lower levels of hockey using birth year to separate age groups so players born late in the year are being matched up with older players at every stage of development and therefor get less ice time and less access to high level coaching. Something worth considering is that because draft year is based off NHL season, the differences in birth month more or less balance out. Players born 6 months into the NHL season are older than ~1/2 their draft class and younger than ~1/2 their draft class. This would not be the case if you based it on birth year. This appears to happen mostly before players hit the NHL radar. What the research on NHL prospects does exist shows that at 18 years old each month of age results in ~1.5% difference in productivity in their respective leagues. There is no evidence I know of that where they were developing matters much unless you are talking some very low level of play, or someplace with sub-par coaching. Some people argue that it’s best to play at the highest level where you will get significant ice time. But my own preference is to see players play at a leave where they can be top players it affords them the opportunity to try new things. A player who is a middling player in their league won’t be afforded much opportunity for mistakes and when they try something new it probably won’t work against better players which would tend to dissuade them from trying new things. This, IMO, tends to lead to a player that makes fewer mistakes but be more risk averse and therefor less high end creativity.