Methods an apparatus for accurately and reliably positioning a device within an egg are provided. An opening is formed within a portion of the shell of an egg and a device is extended through the opening. The device includes a needle having a lumen containing a fluid under pressure. Fluid pressure is monitored and, in response to detecting a change in pressure of the fluid, movement of the device is stopped. Alternatively, fluid flow is monitored and, in response to detecting fluid flow from the needle, movement of the device is stopped. The device may be a substance delivery device that is configured to deliver a substance into the subgerminal cavity of the egg. The device may be a substance removal device that is configured remove a substance from an egg.