Romaine hearts of lettuce the same as romaine??

[Here come the ducks]

Can my ducks have hearts of romaine lettuce ? Is it the same as just romaine lettuce ??
I know this sounds utterly ridiculous... but with these little ones I’m so nervous to feed them
Something wrong! Thank you.

 

[Duck mommy 2019]

yeah i feed them that sometimes and they love it

 

[Here come the ducks]

yeah i feed them that sometimes and they love it

Haha thank you!!
They just had cabbage and kale!! They love it !!