What do I say when I hear a rooster or a dog bark?

The rooster: ask for good

The Prophet ﷺ said: when you hear roosters crowing, ask Allah of His bounty, for they have seen an angel; and when you hear a donkey braying, seek refuge in Allah from Shaytan, for it has seen a devil (Sahih al-Bukhari 3303, Sahih Muslim 2729).

A simple dua is "Allahumma inni as'aluka min fadlik" (O Allah, I ask You of Your bounty). You can also ask for anything good in your own words or language, for example a good day, guidance, or help with a problem.

Dogs barking at night: seek refuge

In another narration, the Prophet ﷺ told us that if we hear dogs barking or donkeys braying at night, we should seek refuge in Allah, because they see what we do not see (Sunan Abi Dawud 5103). Scholars note this is about barking at night, the time when devils spread out. A dog barking at the postman at noon isn't the point of the hadith, though remembering Allah is never wrong.

Say "A'udhu billahi min ash-shaytan ir-rajim" (I seek refuge in Allah from Shaytan, the accursed). That's all. There is no need to panic, go outside, or do anything unusual. See What are jinn in Islam?

What this does and doesn't mean

• Animals aren't bad omens. Islam rejects superstitions about animals bringing bad luck. These sounds are simply reminders to turn to Allah.
• Dogs aren't evil. The hadith is about what animals can sense, not about dogs being cursed. See Can I keep my dog after becoming Muslim?
• It's a sunnah, not a duty. If you forget, there is no sin. It's a small extra reward.

Turning everyday sounds into dhikr

This sunnah shows a beautiful idea: the world around you is full of cues to remember Allah. Rain, thunder, a rooster at dawn, a dog at night, a sneeze. Each has a short phrase attached. Over time, these become automatic and your day fills with small moments of remembrance. A good place to start is your bedtime routine. See What should I say before sleeping?