Could be partly that....and/or it's a later laying breed and/or 'too many boys' stress.
IME, if they don't start laying by mid august, probably gonna have to wait until after solstice.
1 maybe too many for 7.
The 'rooster' to hen ratio of 1:10 that is often cited is primarily for fertility efficiency in commercial breeding facilities.
It doesn't mean that if a cockbird has 10 hens that he won't abuse or over mate them.
Many breeders keep pairs, trios, quads, etc ....short term...