Summer student Anna Garland has done a great job these last couple of months training 12 hens (half from control environments, half from enriched) to learn that a white lidded dish meant mealworms (so, they should flip it for a treat), but a black-lidded dish would, if touched, trigger a nasty airpuff. The hens were trained in a box, and monitored by video, with the dishes being slid in via a slot, all designed to avoid Clever Hans effects. Most hens reached criterion in under 5 days (with around 20 trials a day), making our previous failures with mice and mink look even more pathetic. Some also developed fascinating superstitious responses to the black dish, retreating to a corner, facing away from it or even freezing stock still, as if to avoid being even tempted to touch it.
Once trained, the real aim of the work could start: to present them with intermediate dishes — Shades of Grey (couldn’t resist it) — to see whether they’d be “optimistic” and flip them or “pessimistic” (avoiding them), and in turn whether this judgement bias would be affected by housing. Because we already know our enriched hens are in positive states thanks to the resources they have, a housing effect in the expected direction would validate this novel judgment bias task for poultry (Misha’s Bristol attempts being another noble failure).
Though a bit too early to peek, as Misha another 12 hens to go, Anna had a to make a poster for her summer research course, which forced us to analyse the data. And so far there is a trend, with enriched birds tending to positive-skewed biases….
This is what 
