Young chick (swallow?) found out of nest - ID help please

Hi all,

I think this is a young swallow chick I unfortunately found dead on my porch floor a few days ago at my home in Lancashire. Today the whole nest came down. It was only constructed a few weeks ago in a rather precarious position hence I'm not surprised it failed. On examination I was surprised to see how poorly constructed it was - only made predominately of loose grass/straw and very little mud to knit it together hence I found it hard to believe a swallow could construct a nest so poorly.

I'm assuming whatever species it was, they were inexperienced first timers who've perhaps had repeated failures this season. Please could someone confirm if this chick is a swallow for me? Is it unusual to only have one chick?