We were delighted to find robins nesting in our neglected green house in April. They're currently raising their 4th brood in late June. Is this normal?
It would appear so Bob, most places state 2-3 broods per year starting around Mar/Apr time ...
homeandroost.co.uk/.../encourage-robins-nesting
2013 photos & vids here
eff37 on Flickr
In my area, the same pair have just fledged their 3rd chick, they will breed more if there is an abundance of food and good conditions.
I have read 2-3 as well.