I'm wondering if there is any seasonality in the manufacturing of shuttlecocks or if they just receive a continuous supply of fresh feathers all year long. If there is seasonality (e.g. they receive fresh feathers once a year), when does that occur and when would be the best moment to buy shuttles for 1.5 Years ahead with the freshest feathers?
Feather is a byproduct of raising geese/duck which happens year round in China and other SE Asian countries. I don't think there is a seasonality. Best is to buy them and use them soon after as the oil in the feather can dry out over time. Having said that, if stored correctly and the seal of the tube no broken, they can be stored for a while. I have some from many many years ago that still play like new.
If you humidify them properly, they last a long time. Without humidifying, an Aeroplane Black shuttle lasts us half a game on average. Properly humidified shuttles, usually last us a game or a game and a half. The feathers just don't break, but the shuttle tends to slow down towards the end, which annoys less powerful players who immediately replace it. Recently, I bought GE-92. Without humidifying, it lasted less than half a game, and someone would break a feather or two with a miss-hit. I humidified them 2 days before use, and they last between 1 and 2 whole games and still look and fly good. I usually hold them over steam, but better method is to use cooler water like one from a humidifier. The steam tends to affect the glue, and often the labels fall out, then the brand band at the top of the cork come off. But, other than that, they last well for me.
Where I'm at steaming is not optional. The air is so dry here that shuttles litterally break down in a cloud of dust when you hit them if un-steamed. I use a humidifier from TAAN I'm very satisfied with. Before I was just putting the tubes in the bathroom or sauna which works just as well though slightly more time-consuming.
