Baby flies! (but has bright green poop)--feed?

[poco]

Mommy and Checkers' baby, Baby, flew last week and has done so ever since! Thanks all for the replies.
Here is a picture of Baby on return of his first flight: straight to the water, and right in!

I've been reading some posts about bright green poop - at least Baby has this once a day (starvation?) . These are feral balcony pigeons - but, we feel like we should supplement their food with a bird seed mix. In the winter we did this a few times a week, but all three of them are so active now - and there is so little food in the city.

Is it harmful to give them seed and clean water once a day? We want to make sure they are also still self-sufficient...

Thank you everyone,
Poco