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
Who is talking about what, and a lousy one about the bath.
Free cheese is only in a mousetrap.
A well-fed man does not understand a starving one.
One head is good, but two ones are better.
You can't help grief with tears.
Each sandpiper praises its swamp.
Laws are not written for fools.
If you like sledding, you should like to carry the sled.