thin the herd

have a thin time of it

To be in a difficult or precarious situation due to one not having enough money.

herd cats

To attempt to control the uncontrollable; to attempt to manage a great many unruly factors or people to a single end.

on thin ice

Dangerously, hazardously, delicately.

out of thin air

From nowhere or nothing; from a non-existent or unknown source.

ride herd on

To supervise.

skate on thin ice

To be (or to place oneself) in a risky, potentially dangerous or delicate situation.

spread oneself thin

To commit oneself to too many projects, so that there is little chance of completing them all satisfactorily.

thick and thin

Both good and bad times.