The typical egg-laying period for Barn Owls is the first week of May, though there is always those that nest earlier and later, sometimes much later, as is the case at this nest box in east Kerry.
Four newly hatched Barn Owl chicks, east Kerry, 10th August 2017 (M.O'Clery, under licence from NPWS).
The nest box was checked on Thursday 10th August and the young Barn Owls were just hatching. Eggs are laid one to two days apart, so there is always a difference in size between chicks, yet the oldest was only a few days old, and there were still two unhatched eggs. The eggs would have been laid in the first week of July.
If they survive, the chicks will be fledging in mid-October, an extremely late date.