Bearded dragon soft jaw from blocked UVB

The soft jaw you're seeing is early-stage metabolic bone disease — and the screen mesh lid is almost certainly the main culprit. Standard aluminium or fibreglass mesh blocks 30–50% of UVB before it even reaches your dragon, so even a good bulb can leave them severely deficient over months. Bad lighting is the single most common husbandry mistake with bearded dragons, and the damage often builds quietly before owners notice. To give you the right fix, can you tell me: what size is the enclosure, which UVB bulb are you currently running (brand and wattage), and how old is the dragon exactly?

That compact 10.0 bulb in a dome fitting is a double problem — compact coil UVB bulbs have a very short, concentrated UVB gradient that drops off within 15–20 cm, and the screen on top is cutting what little output it has even further. At one year old she should still be building bone density, so catching this now really matters. The soft jaw and reduced appetite are classic MBD signs at an early, still-reversible stage. Before I recommend the bulb replacement, is the dome fitting currently sitting on top of the mesh, or is the bulb inside the enclosure itself?

That explains everything. At 40–45 cm through mesh, she's been getting a fraction of the UVB she needs — probably less than 20% of what the label implies. Here's what I'd recommend: switch to the Arcadia T5 HO Dragon 12% 39W tube with a Arcadia ProT5 reflector unit, mounted inside the enclosure with no mesh in between, positioned 25–35 cm above the basking zone. The T5 HO 12% is specifically formulated for high-UV species like bearded dragons and gives a wide, even UVB gradient across the full length of a 4-foot viv rather than a narrow hotspot. It's the gold standard for the species. You'll also want to add a proper calcium + D3 supplement to her food daily while she recovers — Repashy CalciumPlus LoD is a good choice. Has she had any vet assessment yet, or are you managing this at home so far?

Honestly, yes — it's a significant upgrade. The Exo Terra compact coil produces UVI readings of around 0.5–1.0 at best at that distance through mesh. The Arcadia T5 HO 12% mounted correctly inside the viv will give you UVI 3–4 in the basking zone, which is where wild bearded dragons actually live. That's not a marginal difference — it's the difference between chronic deficiency and genuine recovery. That said, I'd strongly encourage a vet visit too, ideally a reptile specialist. Soft jaw at this stage can be addressed through lighting and supplementation, but a vet can assess bone density and may recommend calcium injections to accelerate recovery. The lighting fix is essential either way — she cannot improve without it — but don't skip the vet check.

Good — that's the right call on both fronts. While you're reviewing the setup: check your basking spot surface temperature is hitting 45–50°C (use a temperature gun, not a stick-on dial), make sure she has a cool end around 28–30°C, and remove the mesh lid entirely if you can — wooden vivs with front ventilation don't need it and it's only causing harm. Also switch to calcium-rich feeder insects like black soldier fly larvae alongside her usual locusts or crickets. Once the new UVB is in place, give it two to three weeks and you should start seeing her appetite return and jaw firmness improve. The Arcadia T5 HO Dragon 12% 39W with the ProT5 kit is available on Amazon UK — search for the Arcadia ProT5 Dragon 12% 39W 3ft kit and it'll come up as a complete unit with reflector and controller included.