Treats: What's safe & what's not?

[hwrights04]

Our chicks are 5.5 weeks old. What treats are safe to give them on occasion besides mealworms. I've read where some fruits & veggies or their seeds could be harmful to them. What are the safest bets?
Thanks!

 

[Poultry parent]

my chickens love watermelon, sunflower seeds, cucumber (seeds and all), bread, apple ( i don't know about the seeds) peaches (don't give them stone fruit pits as they contain cyanide) milk, stale stuff