With accent marks:
У семи́ ня́нек дитя́ без гла́зу.
~ Seven babysitters make the kid to lose an eye.
The more people take on one task, the less attention is paid to the task.
The closest English equivalent: too many cooks spoil the broth.
Other Russian proverbs
Don’t wave your fists after the fight.
Appetite comes with eating.
Do not look at a given horse's teeth.
An old friend is better than two new ones.
There is no smoke without fire.
Man does not live thanks to bread alone.
A well-fed man does not understand a starving one.
Make a fool pray to God - he will break his forehead.