diff --git a/tests/integration/_support/process.py b/tests/integration/_support/process.py
index 12780540380..23297b28584 100644
--- a/tests/integration/_support/process.py
+++ b/tests/integration/_support/process.py
@@ -260,6 +260,8 @@ def owned_proxy_process(
         "127.0.0.1",
         "--num_workers",
         str(workers),
+        "--timeout_worker_healthcheck",
+        str(int(graceful_stop_seconds())),
         *database_setup,
         *extra_arguments,
     )
@@ -294,6 +296,8 @@ def owned_gateway_image(
         str(workers),
         "--host",
         "127.0.0.1",
+        "--timeout-worker-healthcheck",
+        str(int(graceful_stop_seconds())),
     )
     launch: Final = _launch_until_bound(command, root, environment, output, _PORT_ATTEMPTS)
     try:
@@ -397,9 +401,7 @@ class UpstreamSlot:
 
     __slots__ = ("certificate", "directory", "port", "process", "root")
 
-    def __init__(
-        self, directory: Path, port: int, root: Path, certificate: UpstreamCertificate | None = None
-    ) -> None:
+    def __init__(self, directory: Path, port: int, root: Path, certificate: UpstreamCertificate | None = None) -> None:
         self.directory = directory
         self.port = port
         self.root = root
diff --git a/tests/integration/configuration/test_multi_worker_slow_import_boot.py b/tests/integration/configuration/test_multi_worker_slow_import_boot.py
new file mode 100644
index 00000000000..a90160e5e80
--- /dev/null
+++ b/tests/integration/configuration/test_multi_worker_slow_import_boot.py
@@ -0,0 +1,45 @@
+import os
+import re
+from pathlib import Path
+from typing import Final
+
+import pytest
+from integration._support.client import Gateway, eventually
+from integration._support.process import graceful_stop_seconds, owned_proxy_process
+
+WORKERS: Final = 2
+DEPLOYMENT_HEALTHCHECK_SECONDS: Final = 5
+WORKER_IMPORT_DELAY_SECONDS: Final = 3 * DEPLOYMENT_HEALTHCHECK_SECONDS
+STARTED_WORKER: Final = re.compile(r"Started server process \[(\d+)\]")
+DIED_WORKER: Final = re.compile(r"Child process \[(\d+)\] died")
+SLOW_WORKER_HOOK: Final = f"""\
+import sys
+import time
+
+if "--multiprocessing-fork" in sys.argv:
+    time.sleep({WORKER_IMPORT_DELAY_SECONDS})
+"""
+
+
+def _slow_worker_environment(directory: Path) -> dict[str, str]:
+    hook: Final = directory / "slow_worker"
+    hook.mkdir()
+    (hook / "sitecustomize.py").write_text(SLOW_WORKER_HOOK)
+    return {
+        "PYTHONPATH": os.pathsep.join((str(hook), os.environ.get("PYTHONPATH", ""))),
+        "TIMEOUT_WORKER_HEALTHCHECK": str(DEPLOYMENT_HEALTHCHECK_SECONDS),
+    }
+
+
+@pytest.mark.timeout(2 * graceful_stop_seconds() + 60)
+def test_owned_proxy_workers_outlast_the_deployments_healthcheck_default(gateway: Gateway, tmp_path: Path) -> None:
+    with owned_proxy_process(gateway, tmp_path, _slow_worker_environment(tmp_path), workers=WORKERS) as owned:
+        started: Final = eventually(
+            lambda: STARTED_WORKER.findall(owned.log.read_text()),
+            lambda pids: len(pids) >= WORKERS,
+            seconds=graceful_stop_seconds(),
+        )
+        assert owned.gateway.request("GET", "/health/readiness").status_code == 200
+        log: Final = owned.log.read_text()
+    assert len(started) == WORKERS, log
+    assert DIED_WORKER.findall(log) == [], log
diff --git a/tests/integration/routing/test_priority_scheduler_queue_cleanup.py b/tests/integration/routing/test_priority_scheduler_queue_cleanup.py
index a4606554d34..3c38acadaaf 100644
--- a/tests/integration/routing/test_priority_scheduler_queue_cleanup.py
+++ b/tests/integration/routing/test_priority_scheduler_queue_cleanup.py
@@ -46,7 +46,6 @@ USAGE: Final[dict[str, JsonValue]] = {"prompt_tokens": 5, "completion_tokens": 3
 STARTED_WORKER: Final = re.compile(r"Started server process \[(\d+)\]")
 OWNED_CELL_TIMEOUT: Final = 2 * graceful_stop_seconds() + 120
 PAIR_CELL_TIMEOUT: Final = 3 * graceful_stop_seconds() + 120
-WORKER_HEALTHCHECK_ARGUMENTS: Final = ("--timeout_worker_healthcheck", str(int(graceful_stop_seconds())))
 PINNED_CONNECTION_TIMEOUT_SECONDS: Final = 30
 PINNED_LIMITS: Final = httpx.Limits(max_connections=1, max_keepalive_connections=1, keepalive_expiry=30)
 ENDPOINTS: Final[tuple[Endpoint, ...]] = (
@@ -541,11 +540,7 @@ def test_in_memory_queue_forgets_served_requests_before_a_cooldown(gateway: Gate
     with ExitStack() as stack:
         wire: Final = stack.enter_context(wire_server(answering_model_discovery(upstream.respond)))
         config: Final = owned_config(tmp_path, wire, (INMEM_GROUP,), cooldown_settings(None))
-        owned: Final = stack.enter_context(
-            owned_proxy_process(
-                gateway, tmp_path, {}, config=config, workers=2, extra_arguments=WORKER_HEALTHCHECK_ARGUMENTS
-            )
-        )
+        owned: Final = stack.enter_context(owned_proxy_process(gateway, tmp_path, {}, config=config, workers=2))
         worker: Final = pinned(owned.gateway, stack)
         served: Final = new_marker()
         assert_served(post(worker, "/v1/chat/completions", chat_body(INMEM_GROUP, served, priority=1)), served)
@@ -580,15 +575,9 @@ def pair(tmp_path_factory: pytest.TempPathFactory) -> Iterator[Pair]:
         wire: Final = stack.enter_context(wire_server(answering_model_discovery(upstream.respond)))
         config: Final = owned_config(directory, wire, PAIR_GROUPS, cooldown_settings(cache), cancel_on_disconnect=True)
         overrides: Final = {"REDIS_HOST": cache.host, "REDIS_PORT": str(cache.port)}
-        first: Final = stack.enter_context(
-            owned_proxy_process(
-                gateway, directory, overrides, config=config, workers=2, extra_arguments=WORKER_HEALTHCHECK_ARGUMENTS
-            )
-        )
+        first: Final = stack.enter_context(owned_proxy_process(gateway, directory, overrides, config=config, workers=2))
         second: Final = stack.enter_context(
-            owned_proxy_process(
-                gateway, directory, overrides, config=config, workers=2, extra_arguments=WORKER_HEALTHCHECK_ARGUMENTS
-            )
+            owned_proxy_process(gateway, directory, overrides, config=config, workers=2)
         )
         yield Pair(first.gateway, second.gateway, cache, wire, upstream)
 
@@ -797,9 +786,7 @@ def test_prioritized_requests_survive_a_redis_outage(gateway: Gateway, tmp_path:
             "REDIS_PORT": str(cache.port),
             "REDIS_CIRCUIT_BREAKER_RECOVERY_TIMEOUT": "1",
         }
-        with owned_proxy_process(
-            gateway, tmp_path, overrides, config=config, workers=2, extra_arguments=WORKER_HEALTHCHECK_ARGUMENTS
-        ) as owned:
+        with owned_proxy_process(gateway, tmp_path, overrides, config=config, workers=2) as owned:
             before: Final = assert_all_served(burst(owned.gateway, OUTAGE_GROUP, 12))
             cache.stop()
             during: Final = assert_all_served(burst(owned.gateway, OUTAGE_GROUP, 12))
@@ -826,9 +813,7 @@ def test_sibling_worker_keeps_serving_prioritized_requests_after_a_worker_is_kil
     with owned_redis(tmp_path) as cache, wire_server(answering_model_discovery(upstream.respond)) as wire:
         config: Final = owned_config(tmp_path, wire, (KILL_GROUP,), redis_settings(cache))
         overrides: Final = {"REDIS_HOST": cache.host, "REDIS_PORT": str(cache.port)}
-        with owned_proxy_process(
-            gateway, tmp_path, overrides, config=config, workers=2, extra_arguments=WORKER_HEALTHCHECK_ARGUMENTS
-        ) as owned:
+        with owned_proxy_process(gateway, tmp_path, overrides, config=config, workers=2) as owned:
             workers: Final = eventually(
                 lambda: tuple(int(found.group(1)) for found in STARTED_WORKER.finditer(owned.log.read_text())),
                 lambda pids: len(pids) == 2,