Blucher was not expecting to fight a second day.
The previous evening XIII corps had routed towards Hanover. V and VI corps were retiring towards Celle. IV corps were at Brunswick, but were not expected to attack. Blucher rested his army overnight, but sent one cavalry brigade to pursue XIII corps.
Davout was not aware that IV corps were at Brunswick and had ordered V and VI corps to retire to Celle. He supervised the retreat from high ground north of Peine, and was surprised to see IV corps march towards Peine from Brunswick. He immediately sent orders for V and VI corps to return to support IV corps.
The Prussians lost their only cavalry brigade early in the battle, and the French cavalry were able to delay the Prussian deployment. By midday the Prussian infantry were still deploying.
Meanwhile IV corps was approaching the farm. V corps was back on the battlefield and VI corps returning.
1st Prussian corps has only one infantry brigade and their corps artillery. They took position on a hill overlooking IV corps, but out of sight of the French. By midday they were ready to advance to the northern edge of the hill and fire on the French.
Blucher held a strong central position, but was slow to get into position to defend it
Davout commanded two widely separated wings, and would have to coordinate them both if he was to stand any chance of defeating the Prussians.