This would also depend if you're stocking adults or what is commonly referred to as "feeder" size.
Adult fatheads are in their final stages of life-roughly 17 months.
If you stock now, use feeder size (ave about 1.5" to 2.5") most will be of spawning age/size throughout the entire summer/fall.
If you get full adults now you may loose half of your spawners.
My 2c..
