In this case, the stressed form is necessary if you want to know the gender of the receiver. "Îi" could also be used for the third person feminine pronoun.
it probably should be, but I got it wrong too. Report it. That's how Duolingo learns. Eventually. Unless it is wrong, which could be for some reason I don't know.
Because it is about how usually the words are ordered in Roumanian. I speak fluently and if you say the way you wrotte there, gramaticly is good but no one sais in this way. It sounds to robotic.
StaceyBlas - - " . . . to him . . . ." sounds like a reasonable translation.
It could be correct, technically. However, if the object (the chicken) is the most important information of the sentence, "lui" is skipped: (Lui) Îi dau o găină. Also correct would be: Îi dau o găină lui. The lui placed at the end implies that it is an unexpected recipient of the chicken. (It is HIM that I'm giving the chicken too, not her). If you refer to why it's hen and not chicken, I don't really agree with Duwo on this one. It might better have been a chicken, depending on the context.