Reference article
Seed (Duck Life 1)
The inexpensive food used to build your duck’s energy.
Buying and feeding
Buy seeds in the 
Duck Shop with 
Coins, then feed them to the 
Duckling on the home screen. Eating food increases 
Energy. A normal seed does not train the three racing skills.
Original Flash effect
Each bite of a normal seed gives 1 energy XP in original Flash.
Starting supply
Original Flash, 
Retro Pack and The Flock start with five normal seeds and no Skill Seeds.
Compared with Skill Seeds
In the later Unity editions, five normal seeds cost 5 coins and give the same 3 energy levels as one 10-coin 
Skill Seed. Normal seeds are therefore better value for energy in those editions. Original Flash Skill Seeds have a different effect.
Across the games
Compare games and editions on the Seed page.