要求用双层do loop 语句解决百钱买百鸡问题，编的程序一直不对

求大神指导。下面附上我编的程序，麻烦帮忙看看错哪儿了。谢谢
Sub 百钱买百鸡()
Dim cock, hen, chicken As Long
cock = 1
Do While cock < 20
cock = cock + 1
Do While hen < 33
hen = hen + 1
chicken = 100 - hen - cock
If cock * 5 + hen * 3 + chicken / 3 = 100 Then _
MsgBox "公鸡有" & cock & "只" & vbNewLine & "母鸡有" & hen & "只" & vbNewLine & "小鸡有" & chicken & "只"
Loop
Loop
Debug.Print "公鸡" & cock
End Sub