Most surprising to me is the similar intensity of suffering (“disabling pain”) assigned to nest deprivation as the worst of keel bone fractures. This also seems to be one of the main advantages of cage-free systems over caged ones, with foraging deprivation (with the intensity of “hurtful pain”) being another, based on their charts. The evidence for both is discussed in chapter 6 of their book. They define hurtful and disabling pain here as follows:
Hurtful: experiences in this category disrupt the ability of individuals to function optimally. Different from Annoying pain, the ability to draw attention away from the sensation of pain is reduced: awareness of pain is likely to be present most of the time, interspersed by brief periods during which pain can be ignored depending on the level of distraction provided by other activities. Individuals can still conduct routine activities that are important in the short-term (e.g. eating, foraging) and perform cognitively demanding tasks, but an impairment in their ability or motivation to do so is likely to be observed. Although animals may still engage in behaviors they are strongly motivated to perform (i.e., exploratory, comfort, sexual, and maintenance behaviors), their frequency or duration is likely to be reduced [55]. Engagement in positive activities with no immediate benefits (e.g., play in piglets, dustbathing in chickens) is not expected. Reduced alertness and inattention to ongoing stimuli may be present. The effect of (effective) drugs (e.g., analgesics if pain is physical, psychotropic drugs in the case of psychological pain) in the alleviation of symptoms is expected.
Disabling: pain at this level takes priority over most bids for behavioral execution, and prevents all forms of enjoyment or positive welfare. Pain is continuously distressing. Individuals affected by harms in this category often change their activity levels drastically (the degree of disruption in the ability of an organism to function optimally should not be confused with the overt expression of pain behaviors, which is less likely in prey species). Inattention and unresponsiveness to ongoing stimuli and surroundings is likely to be observed. Relief often requires higher drug dosages or more powerful drugs.
Most surprising to me is the similar intensity of suffering (“disabling pain”) assigned to nest deprivation as the worst of keel bone fractures. This also seems to be one of the main advantages of cage-free systems over caged ones, with foraging deprivation (with the intensity of “hurtful pain”) being another, based on their charts. The evidence for both is discussed in chapter 6 of their book. They define hurtful and disabling pain here as follows: