The Landgraf had contracted to keep his corps up to strength by providing recruits annually to fill the gaps of battle, disease, and desertion. Twice yearly the British muster master assembled and mustered the Hessian regiments and, according to returns which he submitted, Suffolk sent to Schlieffen an estimate of the number of recruits needed for the following campaign. Recruits were collected by the Landgraf's recruiting officers at the depot, first at Rheinfels, and after 1777 at Ziegenhain, and disciplined and drilled as much as time permitted. When the German roads and the river Weser became passable in spring, the British sent instructions to Kassel to put the recruits in motion towards Bremerlehe. The Admiralty Board, notified of probable numbers, provided shipping at two tons per head for the Atlantic crossing. Faucitt was dispatched to the embarkation to inspect the recruits, reject the unserviceable, and swear the remainder into British service. Only then would they receive British pay and emoluments, and the Landgraf his thirty crowns per head.

The usual route for the recruits from Ziegenhain was as follows: to Kassel, where they were paraded on the Rennbahn before the Landgraf, who went through the ranks taking complaints and noting the quality of the recruits; thence to Karlshafen on the Weser, where they were embarked upon barges called Bremerböcke; to Bremen by water, except for those recruits of Prussian origin, who were disembarked to make a roundabout march to avoid Prussian customs at Minden; at Bremen onto lighters, which brought them to the transports.