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The hen was non-barred. The rooster was split. By pure luck yours came out that way.
Look at it this way. As Speckledhen said, the hens only give their gene to the sons, but the father gives a gene to his sons and his daughters.
Use "B" as barred and "b" as not barred. The mother only had a b. The father has Bb, one barred and one not barred. Which gene he gives to his offspring is purely random.
For the female child, she gets either a B or a b from father, so she is either barred or not depending on which she got. In your case all your pullets just happened to get not barred.
For the male child he got a not barred from his mother but will get either a B or a b from his father. By pure luck, all the male offspring were Bb. Since all he needs is one barred gene to show barred, your males were barred.