Day 258. Flying fish and salt horse: a seafaring tale
14th April 1860:

Saturday 14th. Got another nice Chestnut Pony aboard. The owner of it a Scotchman came to try him at first. The Mail arrived but no letters for RPH, rather disappointing.
It obviously wasn’t hard to get another pony to help with loading up the guano. Sounds like it is on loan rather than purchased for the ship.