Case Study: Bilbo – Aggression and Escape Behaviours in a Horse

Written by Abigail Allen, CHBC


Summary: A case study of how past trauma and inadequate current environment can interact to create and maintain problematic behaviors. Bilbo, a young mare with a significant history of aggression and causing injury is sold with the advice that she be euthanized for her behavior. Six weeks later, her new owner called Certified Horse Behavior Consultant Abigail Allen for a consultation, because she is no longer able to be handled at her owner’s facility. Through providing outlets for foraging, opportunities to learn with target training, a proper diet, and the right kind of environmental enrichment, Abigail and her client were able to help Bilbo become more relaxed and significantly less aggressive. 

Case details

Bilbo is a 3-year-old Welsh/Arab cross mare, with no known significant medical history. The client has owned her for six weeks and bought her without undertaking a pre-purchase veterinary examination. No other paraprofessionals have been consulted regarding Bilbo’s behaviour.

Bilbo has been in multiple homes in a short space of time and has had traumatic experiences in each of these environments. She was reportedly “backed” at 2 years old, with little success as she had reared multiple times with both forelegs off the ground putting her in an almost vertical position which unseated the rider. This resulted in the rider going into the hospital due to a suspected fracture. Bilbo was then passed on to a dealer who had also tried to back her with the same outcome. When the client took Bilbo into her care, she was told that Bilbo was dangerous and needed to be euthanised.

Bilbo is stabled in a barn with a straw bed for 21 hours a day, with three hours in a short grass paddock. The paddock does not contain any trees or hedges and the fencing is electrified. She has a companion gelding who is 2 years old. In addition to ad libitum hay Bilbo is fed 1 Stubbs scoop of Allen & Page Calm and Condition with 1 Stubbs scoop of Honeychop Lite chaff. She receives this once a day.

Presenting complaint

The client reported that Bilbo is dangerous to lead to the field and catch to bring back in. She caused injury to two members of staff at the yard by double-barreling them (kicking out both of her hind legs). She is barefoot. She repeatedly jumps out of the field, the arena and her stable, and the injury to the staff occurred when they were trying to catch her after she did so. The client is now in a difficult position, as the yard staff will no longer handle Bilbo, so the client is under pressure to resolve this behaviour or move elsewhere. The client stated that Bilbo is very difficult to handle in general; she is reactive and will not load onto transport. The client is concerned about Bilbo’s refusal to load onto transport in case she does get asked to leave the yard.

Prior interventions

Before turning Bilbo out, the client lunged her for between 30 – 45 minutes to get out “excess energy” when leading her. She stated that when leading Bilbo to the field, the moment that Bilbo rears, she puts pressure on the headcollar by repeatedly yanking on it with the lead rope. Even when Bilbo is not rearing, the client reports putting continuous pressure on the headcollar because Bilbo uses her strength to try to “get away” by pulling against the pressure and swinging her hindquarters toward the client.

When Bilbo has jumped out of the field, arena, and stable, members of staff and the client have herded her into a corner in an attempt to limit her ability to avoid being caught. However, this led to a member of staff being injured so an empty bucket was used instead to lure her. The client and staff felt that the bucket should be empty so that Bilbo wasn’t rewarded for jumping over fences.

Immediate interventions

I referred Bilbo to the veterinarian, and they supplied no relevant medical information that could be contributing to her behavior.

I advised that only she should handle Bilbo, and only during quieter times at the yard when other people are not around, including the client’s children. If the client needed to have her children with her, I advised that they stay in the car when she handles Bilbo outside of the stable. I requested that the client not lunge Bilbo prior to turning her out since this is likely causing her adrenaline levels to increase. I was concerned about the risk of injury to the client. I recommended the client wear a hat, steel toe capped boots, and gloves when she is around Bilbo. As the client lived close by, meaning I could get there quickly, I asked her to leave Bilbo in the stable until our consultation the following day.

Initial consultation

As noted above, I instructed the client to leave Bilbo in on the day of the consultation with her companion next to her. Upon my arrival, Bilbo was in her stable in the barn looking alert. Her ears were flicking back and forth, her head carriage was above wither height, there was triangulation of the eye, her nostrils were flared and her posture was rigid. From the barn, she could see other horses in the paddocks and the activity going on at the yard.

To help settle Bilbo I suggested scattering some treats through her straw bed for her to forage. The client had stated that Bilbo was often alert like this in the barn and she does not eat much of her hay, so I suggested scattering some treats in her hay too.

I spoke to the client regarding Bilbo’s diet as it was high in sugar and starch, which could be contributing to her behaviour since starch that is not digested in the small intestine changes the intestinal microbiota of the hindgut, thus making it more acidic.1 She was being fed Allen and Page Calm & Condition, which has a starch level of 13% and sugar level of 6%. In addition to this she was receiving Honeychop Plus Apple, which has a sugar content of 11.5%. Bilbo is not in need of a diet containing high starch, because her energy requirements are low. I discussed with the client that Bilbo should be receiving a high fibre diet, which would be more suitable, whilst focusing on reducing the sugar content to further reduce the risk of laminitis.

While Bilbo was foraging she began to relax; her upper eyelid was soft, her chin was more relaxed, and she was readily eating her hay without snatching at it. At this point I suggested that we introduced Bilbo to target training, which will be used throughout the training plan. We discussed ways of ensuring that Bilbo remains calm during this training such as feeding prior to training, having a calm companion present, and using a low-value food reward, the chaff she receives in her feed already. I also recommended the client feed Bilbo away from the client’s body whilst ignoring any instances of “mugging” — searching the client’s pockets for food. The stable door was a metal gate, so we utilised this to train in protected contact at first.

For the target, I used a blue Frisbee. I explained to the client that the horse’s vision is dichromatic and we want to make this as easy as possible for her. I demonstrated the protocol to the client whilst explaining what I was doing and why.

The target was held in front of Bilbo where she had to put her head over the gate. A verbal cue of “target” was used. Once Bilbo showed interest in it, I marked the behaviour with a verbal marker of “good” and the target was lowered. Bilbo then received chaff as the reinforcer. Once Bilbo had touched the target with her muzzle, this became the criteria for reinforcement.

The client demonstrated great competency with the training, with excellent timing of her marker, but needed to be reminded to use the cue. Bilbo did not show signs of over-arousal with chaff as the reward, so we continued with it. Bilbo was engaged with the training but occasionally became alert when she could hear horses being ridden past the yard on the road.

I then explained how I wanted the client to turn Bilbo out to the field in a way that was going to be safer. This involved putting several feed buckets from her stable to the field and asking her to target toward each one so that she was focused on walking toward each bucket with her head down. In the field, a bucket with a higher-value food reward was placed in the centre and the client was instructed to unclip the lead rope as Bilbo had her head in the bucket, and then move away.

When Bilbo was brought out of the stable, she appeared very stressed. Her head and neck carriage were high, her nostrils flared, the whites of her eyes were showing, and her tail was elevated. She trotted in a circle around the client and tossed her head. In hindsight, I should have offered a bucket in the stable door when it was opened.

When Bilbo approached the first bucket there was slight relaxation of her body language, though this quickly changed as she began taking big mouthfuls of the food in the bucket and looking up at her surroundings. I instructed the client to cue her to target the Frisbee to encourage her to drop her head back down to the bucket. If she did not want to drop her head back into the bucket, she could target towards the next bucket. When Bilbo was eating out of the final bucket in the field, the client unclipped the lead rope and was able to walk away from Bilbo without her turning her hindquarters in a threat to kick her.

I started with a low-value food to prevent over arousal. However, initially this was not rewarding enough and did not have the desired effect until carrot and apple slices were added to the buckets. Bilbo would still eat the chaff in the buckets but it was not enough to keep her head down and distracted from environmental stimuli. On reflection, when using this bucket method to safely lead Bilbo to and from the field, I should have carried out a food preference test beforehand to further set Bilbo up for success.

I wanted to address Bilbo’s touch aversion in another session; I didn’t feel it was appropriate to do this until the management changes had been implemented.

Because the client was aware of Bilbo’s previous behaviour when ridden, I asked if she had any plans to ride her, and the client asked for my opinion. I explained that Bilbo is still skeletally very immature and has a lot of growing to do. In addition, there is a lot of groundwork to be established in order for Bilbo to trust her handlers before carrying a rider. I advised that when the time comes, she should have a full veterinary examination to ensure she is fit to be ridden. Whilst I could not see any behavioural markers of discomfort, that did not mean she was free from pain.

Differential diagnosis

  • History of trauma and aversive training. Bilbo had been subjected to many incidents of flooding and therefore she may have learnt that her behaviour of turning her hindquarters and threatening to kick creates distance between herself and people, which would have been reinforcing for her.
  • Bilbo was backed extremely young and her growth plates would not have finished fusing. This could have led to the development of pain carrying a rider whilst being skeletally immature, which may have been motivation for her to unseat riders.2
  • Management of Bilbo is poor. She spends a lot of time in the stable, which leads to rebound behaviour when walking her to the paddocks.
  • As she has been labelled dangerous by several people, it could be possible that people automatically begin to handle Bilbo aversively by escalating pressure.
  • Bilbo may have excess glucose stores from inappropriate feeding.

Behaviour modification plan

The following behaviour modification plans were put into place, to be carried out until the second consultation.

Management changes

Following the consultation the safety and management changes recommended were:

  • Use a lunge line when leading Bilbo to the field to ensure that the client can create space between her and Bilbo if she shows any signs of kicking out or rearing.
  • Continue to use the bucket method when turning Bilbo out (see details below).
  • Change diet to reduce sugar and starch levels, feeding Honeychop Lite & Healthy with 3.1% sugar, 0.1% starch, and 31% fibre. As the field is barren and hay loses its nutritional value the longer it is stored, I suggested placing Bilbo on Baileys LoCal balancer to ensure she was receiving a balanced diet.3 This change was to be done gradually over a period of two weeks to allow the digestive system to adapt.
  • Scatter her balancer in her straw bed to encourage her to forage when she is stabled.
  • Feed hay from the floor rather than the haynet to encourage her to eat with her head down and reduce levels of frustration.
  • Scatter her chaff in with her hay to encourage her to forage and consume more of her hay.
  • Increase her turnout time with her companion.
  • Ask if Bilbo can be moved to a quieter part of the yard where she is not exposed to so much traffic and stressors.

As noted above, I told the client to continue to use the bucket method to lead Bilbo to the field And to use a lunge line attached to her headcollar so that space can be created to ensure safety if needed.

I instructed the client to set the buckets out at the same points each time so that Bilbo’s behaviour can be measured. I asked her to keep a diary of Bilbo’s behaviour as she progresses through the buckets, noting points where she seemed more anxious. This way progress can be measured, which is motivating for the client, and patterns may be recognised.

Consult 2

This consultation took place in the afternoon so that Bilbo had time in the paddock before training. Before going to catch her, the client discussed the management changes and changes in her behaviour:

  • Client had switched her diet as instructed.
  • The client noticed a change in Bilbo’s behaviour following the diet change.
  • Bilbo has been moved to a courtyard of stables on the yard as she jumped out of the barn due to farm machinery driving past the barn and hitting the roof. She had not injured herself but was very distressed about being in the barn following this.
  • The client reported that Bilbo seems more settled on the courtyard; she is exposed to fewer stimuli here because it is quieter. She now eats more of her hay and she no longer spends her time alert over the stable door. I was able to confirm this during the consultation.
  • Enrichment items have been added to Bilbo’s stable. Celery had been threaded through a lead rope and secured so that it was hanging in the stable. A rubber ball with holes in was attached to the bottom of the rope and filled with hay and cow parsley.
  • Bilbo was calmer to bring in from the field. She walked by the client’s side and her head carriage remained level with her withers. She walked at a slower pace and the client had the lead rope slack. This informed me that the client has become more confident handling her.

Bilbo was led onto the courtyard where a large holed haynet was tied outside of her stable and the client threaded the lead rope through an Idolo Tether Tie, which allowed for quick release if she panicked.

We began to counter-condition for touch acceptance on the left side, where Bilbo was reported to be easier to handle. The client scratched Bilbo on the shoulder and withers whilst delivering additional positive reinforcement using chaff. Bilbo did not show any signs of being wary until the client began to scratch along her back. Therefore, the client went back a step toward the withers and neck with a high rate of reinforcement. The client then switched to Bilbo’s right side to do the same. When the client switched to the right side, Bilbo turned her head to observe what the client was doing and her posture became more rigid. At this side I instructed the client to remain at her neck where. The scratching there was accompanied by a high rate of reinforcement until Bilbo’s posture changed to become more relaxed again.

The session ended with the client being able to stand behind Bilbo’s shoulder whilst scratching her at the withers. This was a good point to end the session as it was a huge step for the client to be able to stand behind her shoulder without Bilbo swinging her hindquarters towards the client and threatening to kick.

The behaviour modification plan outlined the rest of the protocol to work on touch acceptance. This included a table of the different areas of her body where the client could check off when she could approach Bilbo and scratch this area while Bilbo remained relaxed. This was done for both her left side and right side. To fit this into the client’s routine I suggested that she do this before turning Bilbo out in the field with her companion and when she brings her back onto the courtyard.

Follow-up over phone

The client had seen further improvements in Bilbo’s behaviour. She said Bilbo no longer head tosses as she exits the stable and is much calmer to lead using the buckets. We discussed that over time the distance between these buckets could be increased and eventually faded out to just a bucket in the field to allow the client to safely unclip the lead rope and exit the field.

The client made good progress with the touch acceptance training and is able to groom Bilbo all over, minus her hind legs. The client feels that she is now able to continue the behaviour modification plan independently and her confidence handling Bilbo has improved dramatically. I stressed that the prognosis depends on keeping up with these sessions regularly, even after the client had reached the end goal behaviour, as otherwise there would be risk of spontaneous recovery.4


Whilst Bilbo had become more relaxed in her environment and her handling had become much more predictable for her, addressing her reluctance to load onto transport should be a priority going forward. As Bilbo is young, it is likely that she will move facilities again in her lifetime and she may have to travel in the event of an emergency. If Bilbo is to be ridden in the future, it is also likely that she will be expected to travel to better hacking locations and possibly competitions.

The client’s commitment to following the behaviour modification plan and consistency with the training led to a successful outcome for Bilbo. The client had become attentive to her body language and was able to recognise when to take a step back rather than ask for more.  As the yard staff had been on the receiving end of Bilbo’s dangerous behaviour, they were receptive to making appropriate changes to management due to their interest in the behaviour issue being resolved.

I recommended that the client continue touch acceptance work so that Bilbo would be able to have her hind legs touched and therefore begin the process of being able to handle her hind hooves for the farrier. Whilst the client waits for Bilbo to be skeletally mature, I further recommended that the client uses this time to build up supporting muscle in preparation for carrying a rider as well as counter-condition Bilbo to the tack and equipment that will be used. All this groundwork will go a long way in improving their relationship. I have every confidence that the client will be able to implement future training protocols to fulfil her future goals with Bilbo.


  1. Bulmer, L.S., et al (2019) High-starch diets alter equine faecal microbiota and increase behavioural reactivity. Scientific Reports9:18621
  2. Bennet, D. (2008) Timing and Rate of Skeletal Maturation in Horses, With Comments on Starting Young Horses and the State of the Industry., last accessed 4/28/2022
  3. National Research Council (2007) Nutrient Requirements of Horses: Sixth Revised Edition. Washington, DC: The National Academic Press.
  4. Foster, R. (2016) Relapse of conditioned fear in horses: The four R’s. The IAABC Foundation Journal 1.

Abigail Allen is an IAABC certified horse behaviour consultant and ABTC accredited animal behaviourist. She has a BSc (Hons) in Equine Behavioural Science from Writtle University College. Abigail is passionate about empowering both horse and owner in order to strengthen the horse-human bond and this is her mission with Mind In Motion Equestrian
TO CITE: Allen, A. (2022) Case study: Bilbo — aggression and escape behaviors in a horse. The IAABC Foundation Journal 24, doi: 10.55736/iaabcfj24.8