I note the observation date and time, if the bird was in poor health it will be long past any help. That probably sounds a bit harsh, it isn't intended to sound harsh. However, its very hard to tell on the overall health of the feral pigeon, ideally it would be better to see the overall movement, or an all round closer selection of photos showing eyes, general plumage, legs and other parts.
I'm sorry if this isn't helpful, there may be someone out there who can offer more info, which I would welcome.