In Farming Simulator 25, a manure heap (actually the manure heap extension) must be placed right next to a cow barn/pasture that supports manure production, and the game will only recognize it if it shows as “connected to” that specific animal pen. There is no precise “meter” number given officially, but gameplay and mod discussions indicate it must be within a very short range—basically touching or just a few meters away, and definitely well under 150 m (the loose upper bound mentioned for FS22-style extensions).

Quick answer

  • The manure heap must be placed close enough that the game labels it as “connected to” your cow barn/pasture.
  • In practice, players put it right up against the back fence or wall of the barn , or just a couple of meters away, and that’s enough for it to be recognized and start filling.

What exactly you need

1. Use the extension, not a standalone silo

  • The object that collects manure is called a manure heap extension , found under Silo Extensions , not under regular silos.
  • Placing a normal “manure heap” silo will not make manure accumulate from an animal pen.

2. The animal pen must support manure

  • Only certain pens work: cow stalls/pastures, pig pens, and buffalo pens that explicitly support liquid and solid manure.
  • Pastures for chickens, horses, sheep, etc., do not produce manure, even if you attach an extension nearby.

3. Straw is required

  • Solid manure only appears if the animals have straw :
    • Cows and buffaloes need loose straw (via a cutter/mixer or straw spreader).
    • Pigs can eat straw in bales directly.
  • Without straw, animals only produce liquid manure (slurry), not the solid piles that the heap extension collects.

How “close” is close enough?

The game doesn’t give an exact distance in meters, but all practical guidance and player experience point to:

  • “Right next to” the barn:
    • Many players place the extension flush against the back fence or wall of the cow barn/pasture.
* The UI will show **“connected to: [barn name]”** ; that’s the real indicator that it’s close enough.
  • “A little further away” can still work :
    • One player noted seeing a picture where the extension was “a little further away” but still recognized, suggesting the connection range is not only wall-touching, but still quite small.
  • Upper bound (from FS22-style logic) :
    • A Reddit comment for a similar extension mentions that within 150 m you’ll be fine, but that’s a very generous upper limit; for FS25, the “connected to” prompt is the real check, and that usually only happens when it’s a few meters away at most.

So for FS25 specifically:

  • Aim for touching or 1–3 meters away from the cow barn/pasture.
  • Verify in the UI: if it says “connected to: [your barn]” , it’s recognized and will fill.

Step-by-step checklist

  1. Build a cow barn/pasture that supports manure.
  2. Place straw (loose for cows/buffalo; bales for pigs).
  3. Look in Build → Silo Extensions and place the manure heap extension :
    • Put it right next to the barn , ideally against the back wall/fence.
  4. Open the extension’s info or click on it:
    • Confirm it shows “connected to: [barn name] ”.
  5. Wait: manure volume (in liters) will gradually increase on that heap.

If it doesn’t show “connected to”:

  • Move it closer (try flush against the barn).
  • Double-check you’re using the extension , not a regular silo.
  • Ensure the barn actually supports manure and has straw.

Information gathered from public forums or data available on the internet and portrayed here.