Hand Rearing Youngsters

[Johannes]

Each summer, here in the U.K., temperatures are rising and remaining elevated over a number of weeks. Whilst my American Show Racers are kept in a cool loft, it is well ventilated so warm air does get in.
I’ve not had this issue with my smaller (half the size) tipplers but two summers running I’ve had pairs of ASRs lose interest in reading their 1/3 grown young. Last year two pairs did this and this year three pairs. The photo is of my present hand rearing episode. A lovely, healthy pair of grizzles which were just left to it and chasing every adult bird for food which happened to be nearby. Without doubt, they would have died. Their crops totally empty. On a positive note, they are a very willing breed to hand rear.
Any thoughts appreciated. Has anyone else noticed this?

[AdamArcher]

I recently had a pair give up on sitting just as their eggs were pipping. Very weird and quite annoying as I needed to shuffle the eggs into other nests to save them.