Hello, the cages only produce eggs and feathers each 7 hours cycle, very rarely manure, I think only when the partridge dies and some rarely.
Manure is very important as a fertilizer and for leather work. I suggest that there is manure production in each cycle, not rarely.
One possibility is that the amount produced from the different resources will be different depending on whether the partridges are fed with rye or barley.
Another suggestion is that with much difficulty rarely a partridge incubate an egg and a small partridge is born. The small partridge may need additional care for a few days to grow.